dp3500-4500 sm.pdf

Copyright TOSHIBA CORPORATION 2001ALL RIGHTS RESERVED

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SERVICE MANUAL DIGITAL PLAIN PAPER COPIER DP4500/3500

GENERAL PRECAUTIONS REGARDING THE INSTALLATIONAND SERVICE FOR THE COPIER DP4500/3500

The installation and service should be done by a qualified service technician.

1. Transportation/Installation

• When transporting/installing the copier, employ two persons and be sure to use the positions as

indicated below.

The copier is quite heavy and weighs approximately 73kg (161lb), therefore pay full attention when

handling it.

• Be sure to use a dedicated outlet with AC 115V or 120V/15A (220V, 230V, 240V/10A) or more for

its power source.

• The copier must be grounded for safety.

Never ground it to a gas pipe or a water pipe.

• Select a suitable place for installation.

Avoid excessive heat, high humidity, dust, vibration and direct sunlight.

• Also provide proper ventilation as the copier emits a slight amount of ozone.

• To insure adequate working space for the copying operation, keep a minimum clearance of

80 cm (32”) on the left, 80 cm (32”) on the right and 10 cm (4”) in the rear.

• The socket-outlet shall be installed near the copier and shall be easily accessible.

2. Service of Machines

• Basically, be sure to turn the main switch off and unplug the power cord during service.

• Be sure not to touch high-temperature sections such as the exposure lamp, the fuser unit, the

damp heater and their periphery.

• Be sure not to touch high-voltage sections such as the chargers, high-voltage transformer, IH

control circuit, exposure lamp control inverter, inverter for the LCD backlight and power supply

unit. Especially, the board of these components should not be touched since the electirc charge

may remain in the condensers, etc. on them even after the power is turned OFF.

• Be sure not to touch rotating/operating sections such as gears, belts, pulleys, fan, etc.

• Be careful when removing the covers since there might be the parts with very sharp edges under-

neath.

• When servicing the machines with the main switch turned on, be sure not to touch live sections

and rotating/operating sections. Avoid exposure to laser radiation.

• Use suitable measuring instruments and tools.

• Avoid exposure to laser radiation during servicing.

− Avoid direct exposure to the beam.

− Do not insert tools, parts, etc. that are reflective into the path of the laser beam.

− Remove all watches, rings, bracelets, etc. that are reflective.

3. Main Service Parts for Safety

• The breaker, door switch, fuse, thermostat, thermofuse, thermistor, etc. are particularly important

for safety. Be sure to handle/install them properly.

4. Cautionary Labels

• During servicing, be sure to check the rating plate and the cautionary labels such as “Unplug the

power cord during service”, “Hot area”, “Laser warning label” etc. to see if there is any dirt on their

surface and whether they are properly stuck to the copier.

5. Disposition of Consumable Parts/Packing Materials

• Regarding the recovery and disposal of the copier, supplies, consumable parts and packing mate-

rials, it is recommended to follow the relevant local regulations or rules.

6. When parts are disassembled, reassembly is basically the reverse of disassembly unless

otherwise noted in this manual or other related documents. Be careful not to reassemble

small parts such as screws, washers, pins, E-rings, star washers in the wrong places.

7. Basically, the machine should not be operated with any parts removed or disassembled.

8. Precautions Against Static Electricity

• The PC board must be stored in an anti-electrostatic bag and handled carefully using a wristband,

because the ICs on it may become damaged due to static electricity.

Caution: Before using the wristband, pull out the power cord plug of the copier and make

sure that there are no uninsulated charged objects in the vicinity.

Caution : Dispose of used batteries and RAM-ICs including lithium batteries

according to the manufacturer’s instructions.

Attention : Se débarrasser de batteries et RAM-ICs usés y compris les batteries en

lithium selon les instructions du fabricant.

Vorsicht : Entsorgung des gebrauchten Batterien und RAM-ICs (inklusive

der Lithium-Batterie) nach Angaben des Herstellers.

December 2000 © TOSHIBA TEC 1 - 1 DP4500/3500 SPECIFICATIONS

1. SPECIFICATIONS / ACCESSORIES / OPTIONS / SUPPLIES

1.1 Specifications

Values in [ ] are for DP3500 only when the specifications are different for the DP4500 and the DP3500.

• Copy process Indirect electrophotographic process (dry)

• Type Desktop type (console type when paper feed pedestal (PFP) and large capacity

feeder (LCF) are installed)

• Original table Fixed type (the left rear corner used as guide to place originals)

• Acceptable originals Sheet, book and 3-dimensional object. The automatic document feeder (option)

only accepts paper (64~80 g/m2/17~22 lb.) excluding carbon paper, pasted sheet

and stapled sheet.

Maximum size : A3/LD

• Copy speed (Copies/min.)

* “–” means “Cannot be used”.

* The copy speeds in the above table are available when the originals are manually placed for single-side,

multiple copying.

* When the automatic document feeder is used, the copy speed of 45 [35] sheets per minute is only

available under the following conditions:

• Original/Mode: Single-side originals of A4/LT size. APS and automatic density are

not selected.

• Number of sheets: 45 [35] or more.

• Reproduction ratio: 100%

Paper supply Paper size

A4, LT, B5

A4-R, B5-R,

A5-R, LT-R, ST-R

B4, LG

A3, LD

Cassette

45 [35]

28 [25]

24 [21]

21 [18]

Size specified

45 [35]

28 [25]

24 [21]

21 [18]

Size not specified

21 [18]

21 [18]

21 [18]

21 [18]

PFP

45 [35]

28 [25]

24 [21]

21 [18]

Bypass feeding LCF

(only A4/LT)

45 [35]

–

–

–

DP4500/3500 SPECIFICATIONS 1 - 2 December 2000 © TOSHIBA TEC

* System copy speed (DP4500)

Copy mode Copies/min.

Single-sided originals 1 set 34

x 3 sets 39

Single-sided copies 5 sets 41

Single-sided originals 1 set 19

x 3 sets 28

Two-sided copies 5 sets 30

Two-sided originals 1 set 17

x 3 sets 25

Two-sided copies 5 sets 28

Two-sided originals 1 set 19

x 3 sets 30

Single-sided copies 5 sets 35

* The copy speeds in the table include the time for

the first copy. They are available when the copy

modes in the left-hand table are selected and 10

A4-sized originals are set in the automatic docu-

ment feeder.

• Copy paper

Cassette Duplex copy PFP LCF Bypass copy Remarks

Size A3~A5R A4, LT A3~A5-R, LD~ST-RLD~ST-R (Non-standard or user-

specified sizes can be set.)

Weight 64~80g/m2, 17~22 lb. 64~80 g/m2,17~22lb(Continuous feeding)

50~209 g/m2, 14~55 lb(Single paper feeding)

Special – Tracing paper, labels, Special types of paperpaper OHP film (thickness: 80µm must be recommended

or thicker) by Toshiba

• First copy time .................. 3.9 seconds or faster (A4/LT, upper cassette, 100%, original placed manu-

ally)

• Warming-up time ................ Approx. 30 seconds (standalone, temperature: 20°C)

• Multiple copying................. Up to 999 copies; set number entered with digital keys

• Reproduction ratio .............. Actual ratio: 100±0.5%

Zooming: 25~400% in increments of 1% (25~200% when

using the RADF)

• Resolution/Gradation ......... Read: 600 dpi

......... Write: Equivalent to 2400 dpi x 600 dpi

(primary scanning only : 4 division smoothing)

• Eliminated image width ...... Leading/trailing edges: 2.0±1.0 mm, Side edges: 2.0±2.0 mm


• Paper feeding ..................... Automatic feeding: Copier cassettes–2 cassettes (paper stack height

60.5 mm, equivalent to 550 sheets; 64 to 80 g/m2

(17 to 22 lb.))

PFP–Optional (One cassette or two: paper stack

height 60.5 mm: equivalent to 550 sheets; 64 to 80 g/

m2 (17 to 22 lb.))

LCF–Optional (Paper stack height 137.5 mm x 2:

equivalent to 2500 sheets; 64 to 80 g/m2, 17 to 22 lb.)

Bypass feeding: (Paper stack height 11 mm : equivalent to 100 sheets;

64 to 80 g/m2, 17 to 22 lb.)

• Capacity for originals in the automatic document feeder (Optional)

................. A3~A5-R, LD~ST-R : 100 sheets

• Automatic duplexing unit ... Stackless, Switchback type

• Toner supply ...................... Automatic toner density detection/supply

Toner cartridge replacing method

• Density control .................. Automatic density mode and manual density mode selectable in 11 steps

• Weight ............................... Approx. 73 kg, 161 lb

• Power requirements ........... AC 115V/15A, AC 220 – 240V/10A

• Power consumption ........... 2.0 kW or less (115V series, 200V series)

* Electric power is supplied to the automatic document feeder, finisher, PFP and LCF through the

copier.

• Total counter ...................... Electronic counter


• Dimensions of copier ......... See the figure below (W660 x D673 x H739 mm)

73

9

660

673


1.2 Accessories

Unpacking/setup instructions 1 pc.

Operator’s Manual 1 pc. (not available for MJD)

PM sticker 1 pc. (for MJD)

Setup report 1 set. (for NAD and MJD)

Customer satisfaction card 1 pc. (for MJD)

Developer material 1 pc. (not available NAD and MJD)

Toner cartridge 1 pc. (not available NAD and MJD)

Operator’s Manual pocket 1 pc.

Power cable 1 pc.

Preventive maintenance check list 1 pc. (for MJD)

Toner bag symbol sticker 1 pc. (for MJD)

Warranty sheet 1 pc. (for NAD)

* Machine version

NAD: North America

MJD: Europe

AUD: Australia

ASD: Asia


1.3 Options

Platen cover KA-1600PC

Automatic document feeder (RADF) MR-3012

Paper feed pedestal (PFP) KD-1009

Cassette module MY-1017

Large capacity feeder (LCF) KD-1010

Finisher MJ-1011 (for DP3500), MJ-1012, MJ-1013

Hole punch unit MJ-6001

Staple cartridge STAPLE-1600, STAPLE-600, STAPLE-700

Key copy counter, key copy counter socket MU-8, MU-10

Work table KK-3500

Damp heater kit MF-3500U, MF-3500E

Desk(H) MH-1600H

Desk(L) MH-1600L

System controller GL-1010, GL-1010E

Option for system controller GC-1090 (Extended memory)

GB-1040 (PC-Fax)

GB-1060 (Scan/E-mail Print)

SC-2-TKRING-NIC (TokenRingNIC)

GF-1100 (I/F board for protocol converter)

Printer controller GA-1040

Option for printer controller GC-1080 (Extended memory)

GB-1070 (CWS)

GB-1080 (FreeForm)

GB-1090 (DocBuilderPro)

GE-1020 (PS3 without HDD)

GE-1030 (PS3 with HDD)

Fax unit GD-1080NA/EU/TW/AU

Option for fax unit GD-1090NA/EU (2nd line unit)

1.4 Supplies

Toner PS-ZT3500, PS-ZT3500E, PS-ZT3500D

Toner bag PS-TB3500, PS-TB3500E


1.5 System List

Sta

ple

cart

ridge

STA

PLE

-160

0

Sta

ple

cart

ridge

STA

PLE

-700

Sta

ple

cart

ridge

STA

PLE

-600

Hol

e pu

nch

unit

MJ-

6001

Pap

er fe

ed p

edes

tal (

PF

P)

KD

-100

9

Larg

e ca

paci

ty f

eede

r(L

CF

)K

D-1

01

0

Fin

ishe

r re

lay

unit

Wor

k ta

ble

KK

-350

0

Key

cop

y co

unte

rso

cket

MU

-10

Key

cop

y co

unte

rM

U-8

Aut

omat

ic d

ocum

ent

feed

er (

RA

DF

)M

R-3

01

2

Pla

ten

cove

rK

A-1

600P

C

Fin

ishe

rM

J-10

11

Cas

sette

mod

ule

MY-

1017

Fin

ishe

rM

J-10

13

Fin

ishe

rM

J-10

12

December 2000 © TOSHIBA TEC 2 - 1 DP4500/3500 OUTLINE OF THE MACHINE

2. OUTLINE OF THE MACHINE

2.1 Sectional View

2. OUTLINE OF THE MACHINE

2.1 Sectional View

9 1081

342756

5557

58

11

5652

504849

5154

5347

40 4133

3936 38

37 32

35

34

434245

44

59

62

60

2963

3061

2627

25 24

2328

2218

19

20

21

17

1312 14,15,16

31

46

65

66

DP4500/3500 OUTLINE OF THE MACHINE 2 - 2 December 2000 © TOSHIBA TEC

1 Original glass

2 Exposure lamp

3 Inverter

4 Mirror-1

5 Mirror-2

6 Mirror-3

7 Carriage home position sensor

8 Lens

9 CCD drive PC board

10 Scanner control PC board

11 Laser optical unit

12 Cassette

13 Cassette tray

14 Paper-empty sensor

15 Paper-stock sensor

16 Tray-up sensor

17 Cassette pickup roller

18 Cassette feed roller

19 Cassette separation roller

20 Transport roller

21 Lower feed sensor

22 Upper feed sensor

23 Bypass tray

24 Bypass guide

25 Bypass pickup roller

26 Bypass paper sensor

27 Bypass feed roller

28 Bypass separation pad

29 Registration sensor

30 Registration roller

31 Drum

32 Separation finger for drum

33 Main charger

34 Transfer guide

35 Transfer/separation charger

36 Cleaning blade

37 Recovery blade

38 Toner recovery auger

39 Discharge lamp

40 Toner cartridge

41 Toner motor

42 Developer sleeve (magnetic roller)

43 Doctor blade

44 Mixer-1

45 Mixer-2

46 Auto-toner sensor

47 Fuser unit entrance guide

48 Fuser roller

49 IH coil

50 Fuser roller thermostat

51 Fuser roller thermistor

52 Separation finger for fuser roller

53 Pressure roller

54 Cleaning roller

55 Separation finger for pressure roller

56 Exit finger

57 Fuser unit cover

58 Exit roller

59 ADU upper transport roller

60 ADU middle transport roller

61 ADU lower transport roller

62 ADU entrance sensor

63 ADU exit sensor

64 Paper receiving tray

65 Drum thermistor

66 Humidity sensor


2.2 Location of Electrical Parts[A] Arrang ement of Various Units

ADU

Scanner unit

Main unit

Rear side

Laser unit

System unit


M1

[B] Scanner unit

(B-1) Motor

Rear side

(B-2) Sensors and switches

Rear side

S27

S10

S5S6

S4S3S2

S1

*A4 series : S1 to 5 are installed. LT series : S1 to 3 and S6 are installed.


(B-3) PC boards

(B-4) Others

CCD

SDV

SLGRear side

Rear side

DHM

EXPINV

DHL


LGC

HDD

FAX

NCU-US

BRG

CPU

CD-ROM

FAN-SCPWR-SC

HDD-SC

MDM

SYS

PRT

NIC

HDD-PRT

[C] System unit

Rear side

Fax

Printer

Systemcontroller


[D] Laser unit

Rear side

LDR

SNS

M2

M3

POL

[E] ADU

S24

ADU

CLT1

S22

S23

M4

Rear side


[F] Main unit

(F-1) Motors and fans

(F-2) PC boards and AC parts

M10

M13

M11

M8

M5 M12

M15

M6 M7

M14

IHCOIL

S8

S7

ACC

THERM1

IH

DHC

FUSE

DHD

Rear side

Rear side


(F-3) DC parts except motors and PC boards

Rear side

S9

S26

S30

HVT

ERS

S27S16

CLT4

S31

S28

S17CLT3

CLT6

S25S19

S21S15

CLT7S29

S18

CLT2CLT5

S20

S14

S13

S12

S11

THMS-DTHMS2THMS1


2.3 Symbols and Functions of Various Components

<P-I> indicates page and item number in the parts list.(1) Motors

Symbol Name Function Remarks

M1 SCAN-MOT <P12-I9> Drives the carriages. (B-1)Scanner motor

FAN-SC FAN-534 Cools down the system controller unit. [C]System controller cooling fan [Optional]

M2 M/DC-POL-320 Drives the polygonal mirror. [D]Polygonal motor

M3 FAN-DC-320 <P7-I28> Cools down the laser optical unit. [D]Laser unit fan

M4 ADU-MTR <P32-I18> Drives the ADU. [E]ADU motor

M5 MAIN-MTR <P11-I26> Drives the drum, developer unit and fuser (F-1)Main motor unit.

M6 EXIT-MTR <P6-I11> Drives the exit roller. (F-1)Exit motor

M7 TNR-MTR <P27-I9> Supplies the toner. (F-1)Toner motor

M8 T-UP-MTR <P4-I22> Drives the cassette tray upward. (F-1)Tray-up motor

M10 SP-FAN <P10-I2> Assists the paper separation by suction. (F-1)Sub-separation fan

M11 EXIT-FAN <P10-I2> For exhaustion. (F-1)Exhaust fan

M12 IH-FAN <P8-I3> Cools down the IGBT for fuser control. (F-1)IH control board cooling fan

M13 MID-FAN <P8-I3> Cools down the drum and cleaner unit. (F-1)Middle cooling fan

M14 FUSER-FAN <P29-I13> Cools down the fuser unit. (F-1)Fuser unit cooling fan

M15 DEV-FAN <P6-I33> Cools down the developer unit. (F-1)Developer unit cooling fan



(2) Sensos and switches

S1-6 APS1-6 <P9-I17,18> Detects the size of originals. (B-2)Automatic original detection sensor

S10 HOME-SW <P9-I22> Detects the home position of the carriage. (B-2)Carriage home position switch

S27 PLTEN-SNR <P12-I15> Detects if the platen cover is opened/closed. (B-2)Platen sensor

S22 ADU-TRU-SNR <P32-I31> Detects paper in the paper entrance area [E]ADU entrance sensor of the ADU.

S23 ADU-TRL-SNR <P32-I31> Controls paper transport in the ADU. [E]ADU exit sensor

S24 ADU-SET-SW <P32-I43> Detects if the ADU is opened/closed. [E]ADU opening/closing switch

S7 MAIN-SW <P5-I10> Shuts off the AC power to the copier. (F-2)Main switch

S8 DOOR-SW <P5-I7> Interlock switch to shut off the AC power (F-2)Front door switch when the front cover is opened.

S9 EXIT-SNR <P30-I21> Detects paper in the paper exit area. (F-3)Exit sensor

S11 TNR-SW <P27-I23> Detects the toner cartridge. (F-3)Toner cartridge detection switch

S12 SNR-ATC <P25-I19> Detects the toner density. (F-3)Auto-toner sensor

S13 RGST-SNR <P18-I11> Detects if paper has reached the registration (F-3)Registration sensor roller.

S14 FED-U-SNR <P18-I11> Detects paper misfeeding. (F-3)Upper feed sensor

S15 FED-L-SNR <P18-I5> Detects paper misfeeding. (F-3)Lower feed sensor

S16 NEMP-U-SNR <P13-I27> Informs that the upper cassette is almost (F-3)Upper cassette paper-stock sensor empty.

S17 NEMP-L-SUR <P13-I27> Informs that the lower cassette is almost (F-3)Lower cassette paper-stock sensor empty.

S18 EMP-U-SNR <P13-I27> Detects presence/absence of paper in the (F-3)Upper cassette paper-empty sensor upper cassette.

S19 EMP-L-SNR <P13-I27> Detects presence/absence of paper in the (F-3)Lower cassette paper-empty sensor lower cassette.

S20 TOP-U-SNR <P13-I27> Detects if the upper cassette tray has been (F-3)Upper cassette tray-up sensor lifted to the upper limit.

S21 TOP-L-SNR <P13-I27> Detects if the lower cassette tray has been (F-3)Lower cassette tray-up sensor lifted to the upper limit.

S25 CST-COVER-SW <P5-I19> Detects if the the side door is opened/ (F-3)Side door switch closed.

S26 F-COV-SW <P5-I7> Detects if the front cover is opened/closed. (F-3)Front cover switch

S27 CST-U-SW <P4-I5> Detects if the upper cassette is installed. (F-3)Upper cassette detection switch

S28 CST-L-SW <P4-I5> Detects if the lower cassette is installed. (F-3)Lower cassette detection switch




(3) Electromagnetic spring clutches

CLT1 ADU-CLT <P32-I16> Drives ADU. [E]ADU clutch

CLT2 FED-U-CLT <P13-I14> Drives the pickup roller for the upper (F-3)Upper cassette feed clutch cassette.

CLT3 FED-L-CLT <P13-I14> Drives the pickup roller for the lower (F-3)Lower cassette feed clutch cassette.

CLT4 RGST-CLT <P18-I31> Drives the registration roller. (F-3)Registration clutch

CLT5 TR-L-CLT <P14-I20> Transport paper from the registration area. (F-3)Transport clutch (low speed)

CLT6 TR-H-CLT <P14-I16> Transport paper up to the registration area. (F-3)Transport clutch (high speed)

CLT7 SFB-CLT <P16-I17> Drives the bypass pickup roller. (F-3)Bypass feed clutch

(4) Heaters and lamps

EXP LP-EXPO-50K-320 <P20-I2> Exposes the original with light. (B-4)Exposure lamp

DHM DNP-HTR <P9-I8> Prevents condensation in the scanning area (B-4)Damp heater (for mirrors).

DHL DNP-HTR <P9-I30> Prevents condensation in the scanning area (B-4)Damp heater (for lens).

DHD D-HTR-L <P26-I7> Keeps the drum and transfer/separation (F-2)Lower damp heater charger warm.

DHC D-HTR-CST <P4-I34> Prevents condensation in the cassettes. (F-2)Cassette damp heater

IHCOIL IH-COIL <P30-I23> Heats up the fuser roller. (F-2)IH coil

ERS LP-ERS <P24-I33> Removes the residual charge from the drum (F-3)Discharge lamp surface.


S29 SFB-SNR <P17-I25> Detects presence/absence of paper in the (F-3)Bypass paper sensor bypass tray .

S30 T-FUL-SNR <P11-I28> Detects if the toner bag is full. (F-3)Toner bag full detection sensor

S31 HUMI-SNR <P7-I25> Detects humidity inside the copier. (F-3)Humidity sensor




(5) PC boards

SLG PWA-F-SLG-320 <P9-I13> Controls the scanner section. (B-3)Scanner control PC board (SLG board)

CCD PWA-F-CCD-320 Controls pre-processing of the CCD image (B-3)CCD drive PC board (CCD board) data.

SDV PWA-F-SDV-320 <P12-I22> Controls the scanner motor. (B-3)Scanner motor drive PC board (SDV board)

SYS PWA-F-SYS-320 <P7-I18> General control of the copier and data [C]System PC board (SYS board) processing.

LGC PWA-F-LGC-320 <P7-I19> General control of the copier [C]Logic PC board (LGC board)

FAX PWA-F-FAX-527 <P1-I11> Controls the fax function. [C]Fax control board [Optional]

MDM PWA-F-MDM-528 <P2-I15> Controls dialing for the analog circuit (2nd [C]Telephone circuit control board circuit) [Optional]

NCU-US PWA-F-NCU-US <P1-I12> Controls dialing for the analog circuit (2nd [C]Telephone circuit control board circuit) [Optional]

PRT PWA-F-PRT-533 Controls the printer function. [C]Printer control board [Optional]

NIC NIC Connects the printer with the network. [C]Network board [Optional]

BRG PWA-F-BRG-534 Connects the system controller with the [C]Bridge board copier. (PCI to PCI bridge board) [Optional]

CPU PWA-F-SBC-534 Controls the system controller. [C] System controller CPU board [Optional]

LDR PWA-F-LDR-320 Drives the laser diode. [D]Laser drive PC board (LDR board)

POL M/DC-POL-320 Drives the polygonal motor. [D]Polygonal motor drive board

SNS PWA-F-SNS-320 Detects the laser beam position. [D]H-Sync detection PC board

ADU PWA-F-ADU-320 <P32-I30> Drives the ADU. [E]ADU board

IH PS-IH-320 <P31-I2> Controls the IH of the fuser unit. (F-2)IH control board

FUSE PWA-F-FUS <P6-I36> Prevents over-current being supplied to the (F-2)Fuse PC board damp heaters.

HVT PS-HVT-320 <P4-I29> Generates the voltage for the following: (F-3)High-voltage transformer • main charger wire

• main charger grid• developer bias• transfer charger wire• separation charger wire• transfer guide bias

(6) Transformer


INV INV-EXP-50K-320 <P20-I3> Controls the exposure lamp. (B-4)Lamp inverter

HDD HDD <P7-I15> Stores the image data. [C]Hard disk

HDD OPTION-HDD-533 Extends the functions of the printer. [C]-PRT Hard disk (for printer) [Optional]

CD-ROM CD-ROM-534 A part of the system controller. Reads the [C]CD-ROM drive data. [Optional]

HDD HDD-534 Sub-memory for the system controller. [C]-SC Hard disk (for system controller) [Optional]

PWR PS-534 Power supply for the system controller [C]-SC Power supply for system controller [Optional]

ACC PS-ACC-320 <P6-I26> Provides the electrical power. (F-2)Switching power supply

THERM1 THERMO-HTR <P28-I9> Prevents the over-heating of the fuser unit. (F-2)Thermostat

THMS-D THMS-DRM <P25-I29> Detects the surface temperature of the (F-3)Drum thermistor drum.

THMS1 THMS-HTR <P28-I10> Detects the surface temperature of the (F-3)Fuser roller center thermistor center area of the fuser roller.

THMS2 THMS-S-HTR <P28-I10> Detects the surface temperature of the ends (F-3)Fuser roller side thermistor of the fuser roller.


(7) Others


2.4 System Block Diagram

Imag

e D

ata

Ser

ial-I

/F

PW

A-F

-SLG

-320

PW

A-F

-LG

C-3

20

SR

AM

256K

B

NV

RA

M8K

Bx8

S-C

PU

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2.5 Installation and Removal ofCovers and PC board

2.5.1 Installation and removal of covers

[A] Front cover

(1) Open the front cover.

(2) Pull up the hinge pins on the left and the right,

then extract them.

(3) Remove the front cover.

[B] Front side right cover

(1) Pull out the upper cassette.

(2) Open the front cover, bypass unit and ADU.

(3) Remove 2 screws.

(4) Remove the front side right cover.

[C] Feed side front hinge cover

(1) Pull out the upper and lower cassettes.

(2) Remove 2 screws and take off the feed side

front hinge cover.

[D] Feed side rear hinge cover


rear hinge cover.

Hinge pin Front cover

Front side right cover

ADU

Bypass unit

Feed side front hinge cover

Feed side rear hinge cover


[E] Feed side upper cover

(1) Open the bypass unit, ADU, jam access cover

and fuser unit cover.


(3) Slide the feed side upper cover to the left to

take it off.

[F] Feed side lower cover

(1) Remove the feed side rear hinge cover.

(2) Open the bypass feed unit and ADU.


lower cover.

[G] Rear side upper cover

(1) Remove 4 screws and take off the rear side

upper cover.

[H] Rear side lower cover


(2) Slide the rear side lower cover to the right to

take it off.

[I] Receiving tray

(1) Open the front cover.


(3) Slide the receiving tray upwards to the left to

take it off.

Fuser unitcover

ADUJam accesscover

Feed sidelower cover

Rear sideupper cover

Rear sidelower cover

Receivingtray

Feed sideupper cover


[J] Tray bac k co ver

(1) Remove the receiving tray.

(2) Take off the feed side upper cover.


(4) Slide the tray back cover to the left and take it

off.

[K] Left cover

(1) Remove 3 screws and take off the left cover.

[L] Option cover

(1) Slide the cover in the direction of the arrow and

take it off.

[M] Exit side rear cover

(1) Take off the rear side upper/lower covers.

(2) Loosen the screws of the receiving tray and left

cover.

(3) Remove 4 screws and take off the exit side rear

cover.

Left cover

Option cover Receivingtray

Leftcover

Tray back cover

Rear sideuppercover

Rear sidelowercover

Exit siderear cover


[N] Left top cover


[O] Right top cover


[P] Rear top cover

(1) Loosen the screws of the left top cover and right

top cover.


[Q] Front top cover

(1) Loosen the screws of the left top cover.

(2) Loosen the screws of the right top cover.

(3) Remove 3 rubber screw caps.


[R] Control panel lower cover

(1) Loosen the screws of the left top cover.

(2) Loosen the screws of the right top cover.


Left topcover

Rear top cover

Right topcover

Fronttop cover

Controlpanel lowercover

[O]

[Q]

[P]

[N]

[O]

[O]

[O]

[Q][Q]

[N]

[P]


2.5.2 Installation and removal of PC board

[A] Logic PC board (LGC board)

(1) Remove the paper receiving tray and left cover.

(2) Remove 7 screws and take off the stay.

(4) Disconnect 14 connectors, remove 2 screws and

detach 2 lock supports.

Take out the logic PC board

Note: When installing the logic PC board, connect

it securely with the system PC board.

[B] System PC board (SYS board)

(1) Remove the logic PC board.

(2) Take off the rear side upper/lower covers and

exit side rear cover.

(3) Remove 7 screws. Take off the plate cover of

the rear side of the system unit.

Plate cover

Lock support Logic PC board

(3) Remove 4 screws and take off the plate cover

of the system unit.

Stay

Laser unit fan


(4) Disconnect 4 connectors and remove 6 screws.

Take off the system PC board.

[C] Hard disk (HDD)

(1) Take off the logic PC board.


Take out the hard disk with the metal plate at-

tached.

(3) Remove 4 screws and take the hard disk apart

from the metal plate.

[D] Scanner control PC board (SLG board)

(1) Take off the right top cover. Remove the original

glass.

(2) Remove 7 screws and disconnect one connector.

Take off the lens cover.

[Rear side]

[Front side]

Connector

SystemPCboard

System PC board Connector

Connector HDD

Lens cover

Connector



Take out the scanner control PC board.

[E] High-voltage transformer

(1) Take off the rear side lower cover.

(2) Disconnect 7 connectors, remove one screw and

detach 3 lock supports.

Take off the high-voltage transformer.

Lock supportHigh-voltage transformer

ScannercontrolPC board

Note: Connect the connectors as shown in the figure below.

Harness: white/connector: blue(developer bias output)

Harness: white/connector: white(tranfer bias output)

Harness: black/connector: blue(separation charger output)

Harness: red/connector: red(transfer charger output)

Input connector

Harness: white/connector: white(Main charger grid output)

Harness: red/connector: red(Main charger output)


[F] Switching power supply

(1) Take off the left cover and rear side lower cover.

(2) Disconnect one connector from the rear side.


Pull out the switching power supply.

[Rear side]

[Exit side]

Connector

Connector

Do not disconnect this connectorhaving 3 connector pins.

December 2000 © TOSHIBA TEC 3 - 1 DP4500/3500 COPY PROCESS

–

––

––

–

–

–––

––

–

–+

+++ –

+

+++

+

+

+

––

–

––

– –

––

3. COPY PROCESS

3.1 General Description of Copying Process

(1) Charging: Applies negative charge on the sur-

face of the photoconductive drum.

x

(2) Original exposure: Converts images on the

original into optical signals.

x

(3) Data reading: The optical signals are converted

into electrical signals.

x

(4) Data writing: The electrical signals are converted

into light signals (laser emission) which exposes

the surface of the photoconductive drum.

x

(5) Development: Negatively-charged toner ad-

heres to the photoconductive drum and forms

visible image.

x

(6) Transfer bias: Improves transfer efficiency.

x

(7) Transfer: Transfers the visible toner image on

the photoconductive drum onto paper.

x

(9) Separation: Separates paper with the toner

image from the photoconductive drum.

x

(9) Fusing: Fuses the toner image onto the paper

by applying heat and pressure.

x

(10) Cleaning : Scrapes off the residual toner from

the drum.

x

(11) Discharge LED array: Eliminates the residual

negative charge from the surface of the photo-

conductive drum.

Original exposureXenon lamp

20 W

Data writingSemiconductive laser

Pw=4.0 nJ/mm2

Charging

–790V(grid voltage)

Discharge LED array

Wavelength 660 nm x14 pcs

DevelopmentMagnetic rollerBias –550VDC

+150VDCBypass feeding

(100 sheets)

PFP (upper/lower)(550 sheets) or

LCF(1250 sheets x 2)

Cassette feeding(upper/lower)(550 sheets)

TransferH 286µAC 286µAL 137µA

SeparationACH 4.8kV

C 4.5kVL 2.9kV

DC -100V1kHz

Data reading(scanning)

CCD600 dpi,7450 pixel

Image processing

Cleaning

Paper discharge

FusingInduction heating method

700~1300W

Transfer biasDC+580V

Toner

Carrier

(2)

(3)

(1)

(4)

(11)(10)

(9)

(8)

(7)

(6)(5)

DP4500/3500 COPY PROCESS 3 - 2 December 2000 © TOSHIBA TEC

3.2 Details of Copying Process(1) Photoconductive drum

The photoconductive drum consists of two layers.

The outer layer is a photoconductive layer made of

an organic photoconductive carrier (OPC), and the

inner layer is an aluminum conductive base in a

cylindrical form.

The photoconductor has the following property: when

it is exposed to light, the electrical resistance it pos-

sesses increases or decreases according to the

strength of the light.

Example:

· Strong lightn

Resistance is decreased (works as a conductor.)

· Weak lightn

Resistance is increased (works as an insulator.)

[Formation of electrostatic latent image]

In the processes of charging, data reading, data

writing, discharging described later, negative poten-

tial of the areas on the drum corresponding to black

areas of the original are eliminated, while the areas

on the drum corresponding to white areas retains

the negative charge.

As this image on the drum formed by the negative

potential is not visible, it is called an “electrostatic

latent image.”

(2) Charging

Charging is the process to apply charge evenly on

the drum surface.

The charger wire produces negative corona discharge

is controlled by the grid, allowing the drum surface

to be evenly charged with the negative potential.

The surface potential on the drum is determined by

the grid potential and is controlled to a certain value

by the grid control circuit.

Photoconductive layer

Base

Structure of the photoconductive drum(Example of OPC)

0

– 500

– 1000

Time (t)

Black area of original

White area of original

Sur

face

pot

entia

l (V

)

Dischargeprocess

Chargingprocess

Electric potential of the photoconductive drum

Main charger

Drum rotation

Grid control circuitHigh-voltagetransformer


(3) Data reading (scanning)

Data reading is the process of illuminating the origi-

nal with light and converting the reflected light into

electrical signals.

The light reflected from the original is directed to

the charge coupled device (CCD) and this optical

image information is converted into electrical sig-

nals (image signals), which are then sent to the

image processing section.

CCD

Image processingsection

(Example)

CCD lightreceivingamount

Value of imagesignals to beoutput

Blight 255

Dark 0

Difference between"blight " and "dark" isdivided into 256 steps.

(4) Data writing

Data writing is the process of converting the image

signals sent from the image processing section into

optical signals and exposing the drum surface with

the light.

Semiconductive laser element converts image sig-

nals sent from the image processing section into

optical signals (laser emission) to expose the drum

surface and form an electrostatic latent image on it.

Imageprocessing

section

Laser driveboard

Semiconductivelaser element

Polygonal mirror

Photo-conductive

drum

u

u


(5) Development

Development is the process of making the electro-

static latent images visible to the eye (visible im-

ages).

Developer material is supplied to the photoconduc-

tive drum surface by the magnetic roller. The toner

in the developer material adheres to the areas on

the drum surface where the potential is lower than

the developer bias which is applied to the magnetic

roller (reverse development method).

Photoconductive layer

The (–) potential of thephotoconductive drum ishigher than the developerbias.

The (–) potential of thephotoconductive drum islower than the developerbias.

Drum

Magnetic roller

Magnet

Magnetic roller Toner

Carrier (always attractedonto the magnet)

Toner

Bias voltage–550 VDC

Photocon-ductivedrum

Aluminum base

Toner

0

– 100V

– 200V

– 300V

– 400V

– 600V

White background Half tone Solid

White backgroundImage not developed

BiaspotentialImage developed by

toner

750

550


• Switching of developer bias polarity

With the area which has no negative change, back-

ground fogging is decreased by switching the bias

to the positive polarity (approx. +150V).

• Developer material

The developer material consists of a mixture of the

toner and carrier. The toner is charged to the negative

polarity and the carrier to positive polarity due to the

friction with each other caused by mixing.

Toner : Mainly consists of the resin and carbon.

Carrier : Consists of the ferrite and resin coating on

its surface to provide consistent frictional

electrification.

Note:

If the developer material is used for a long time

(beyond its normal life span),

the toner is caked onto the carrier.

x

The carrier’s (charging) performance is lowered.

Symptom: 1. Image density is lowered.

2. Toner scattering occurs.

3. Background fogging occurs.

Solution: Replace the developer material.

• Magnetic roller

- Magnetic brush development -

The south and north poles are arranged inside the

magnetic roller as shown in the right figure. The de-

veloper material forms a brush-like fluff which con-

tacts the photoconductive drum surface.

x

This is caused by the magnetic force lines between

the south and north poles.

Carbon(5~10%)

Resin (90~95%)

[Toner]

5~20µmFerrite

30~100µm

[Carrier]

TonerCarrier

No frictional electrificationoccurs on the area wherethe toner is caked on.

NSS

Magnetic forceline

Magnetic roller

Photoconductivedrum


Additional Explanation

The life of the toner cartridge (number of copies) varies depending on the following conditions.

1. Coverage of originals (printing image ratio of the original size) and density of original background

2. Size and density of originals

3. The existence of solid black when making copies (when a book is copied and the original cover is

partially opened)

4. Temperature and humidity in the room when making copies

5. Copy density and image quality mode

As indicated in the figure below, the life of the toner cartridge varies depending on the copy mode and

coverage of originals.

Type of originals

A.

B.

C.

ＡＡＡＡ

5,000

10,000

ＡＡＡＡ

ＡＡＡＡ

ＣＣＣＣ

15,000

ＢＢＢＢ

20,000


(6) Transfer

Transfer is a process of transfering the toner image

(visible image) formed on the drum surface onto

paper.

Method: A paper passing the side of the drum is

charged to the opposite polarity to the

toner's by the corona discharge of the

transfer charger.

x

The toner moves from the drum surface

onto the paper.

* For smooth transfer

In the transfer bias processing of this copier, bias

voltage (+580VDC) is applied to the pre-transfer

guide to prevent the charge produced by the trans-

fer charger from flowing into the pre-transfer guide

through the paper.

The corona discharge applied to the paper is nor-

mally 286µA DC. However, to improve transferabil-

ity at the trailing edge of the paper, lower output

(137µA DC) is applied to the part 10 mm from the

trailing edge.

(7) Separation

Separation is the process of separating paper which

is temporalily adhering to the drum due to the static

electricity during the transfer process.

Method: Apply AC voltage to which the negative

DC bias is added to the separation charger.

x

The positive charge on the paper is de-

creased.

x

The static electricity (adherence power) be-

tween the paper and drum becomes weak.

x

The paper is separated from the drum by

its own stiffness and absorption by the fan.

DrumPaper

Transfercharger

Toner

Drum rotation

Direction oftransportation

Transfer charger

Direction oftransportation

Drumrotation

Separation charger

Absorbing

Suction fan(Sub-separation fan)

u


* Output is controlled as follows to realizes the desirable separability and transferability.

Paper position against transfer point Separation output

From leading edge to 10 mm from leading edge (H) 4.8kV AC/–100 V DC

From 10 mm from leading edge to 17 mm from trailing edge (C) 4.5kV AC/–100 V DC

From 17 mm from trailing edge to trailing edge (L) 2.9kV AC/–100 V DC

Paper may not be separated from the drum

surface because of moisture or malfunction of

the transfer/separation charger. As the result,

the paper gets into the cleaner and causes

jamming. To prevent this, a separation finger is

used to forcibly separate the paper which was

left around the drum.

(8) Fusing

Fusing is the process of melting the toner on the

paper and fixing it firmly on the paper.

Method : The melting point of the toner (main in-

gredient : resin) is 100~110°C.

x

(Heat) Toner is melted by the heat of the sur-

face of the fuser roller.

+(Pressure) The pressure roller is pressed against

the fuser roller by the springs to increase

the adherence of the melted toner onto

the paper.

x

Heat and pressure are applied to the

paper when it passes between the fuser

roller and pressure roller.

||

(Fusing) The toner is fused on the paper.

Papermovement

IH coil

Fuser roller

Pressure roller

Separation finger

Separation finger

Drum rotation

Papermovement

Separationcharger

Fuser roller

Paper

Pressure

(Pressure)

Separation finger


(9) Cleaning

Cleaning is the process of removing the residual

toner from the photoconductive drum.

The edge of the urethane rubber cleaning blade is

pressed against the photoconductive drum surface

to scrape off the residual toner on it. The toner is

then caught by the recovery blade.

(10) Discharging

Discharging is the process of eliminating the negative

charge remaining on the photoconductive drum

before the next charging process.

If the residual charge is not eliminated, the follow-

ing phenomenon occurs:

Uneven charge is applied to the drum during the

next copying.

x

The next copy will have a double image. (The

preceding image appears.)

Solution :

The entire surface of the photoconductive drum

is illuminated with light by the discharge LED

array.

x

The photoconductive drum becomes electri-

cally conductive.

x

All of the negative charge remaining on the pho-

toconductive drum is conducted to the ground.

x

Preparation for the next copying is completed.

Discharge LED array

Photoconduc-tive drum

Ground

Cleaning blade

Drum rotation

Recovery blade


Process

1. Photoconductive drum

(1) Sensitivity

(2) Surface potential

2. Charging

3. Data writing(1) Light source

(2) Light amount

4. Development(1) Magnetic roller

(2) Auto-toner

(3) Toner supply

(4) Toner-empty detection

(5) Toner

(6) Developer material

(7) Developer bias

5. Transfer bias

6. Transfer

7. Separation

8. Discharge before cleaning

9. Discharge

(1) Discharging position

(2) Discharge lamp

10. Cleaning

(1) Method

(2) Recovered toner

11. Fusing(1) Method

(2) Cleaning

(3) Heater

3580 DP4500/3500

OD-2460 (OPC ø60) OD-3500 (OPC ø60)

Highly sensitized/durable drum Same as 3580

(Grid voltage –736 V) –750 V (grid voltage –790V)

Scolotron method (constant current) Same as 3580

Adjustable grid output (constant Same as 3580voltage)

Semiconductive laser (adjustment Same as 3580not required)

3.5 nJ/mm2 4.0 nJ/mm2

One magnetic roller Same as 3580

Magnetic bridge-circuit method Same as 3580

Toner cartridge Same as 3580

Density detection method Same as 3580

T-3580, T-3580E, T-3580D T-3500, T-3500E, T-3500D

D-3580 D-3500

DC–510V Adjustable output DC–550V Adjustable output(during printing) (during printing)

DC+150V (fixed) (others) DC+150V (fixed) (others)

Adjustment not required Same as 3580

Adjustable output (constant current) Same as 3580

AC:Adjustable output (constant Same as 3580current)

DC:Adjustment not required

AC:Adjustable output (constant Not availablecurrent)

DC:Adjustment not required

Exposure after cleaning Same as 3580

Red LED Same as 3580

Cleaning blade Same as 3580

Cannot be reused Same as 3580

Long-life fuser roller method Same as 3580•Fuser roller: •Fuser roller:Coated with fluoroplastic (ø40) Coated with fluoroplastic (ø40)

•Pressure roller: PFA tube roller (ø35) •Pressure roller: PFA tube roller (ø30)

•Cleaning roller for fuser roller (ø20) •Cleaning roller for pressure roller (ø14)

•Cleaning felt roller for fuser roller (ø18)

Halogen lamp (Lamp-heating method) IH coil (Induction-heating method)

Turned ON/OFF by thermistor Same as 3580

3.3 Comparison with 3580

December 2000 © TOSHIBA TEC 4 - 1 DP4500/3500 GENERAL OPERATION

4. GENERAL OPERATION

4.1 Overview of OperationOperation of copier Operation during initializing, pre-running and standby status

Cassette feed copying by START key

Copying operation Bypass feed copying

Interrupt copying

4.2 Description of Operation4.2.1 Warming-up

(1) Initialization

• Power is turned ON.

• The IH coil comes ON.

• Set number “1” and “WAIT WARMING UP” are displayed

• The fan motors are turned ON.

• Initialization of the scanner system

~ The carriages move to the home position.

~ The carriages move to the peak detection position.

~ The exposure lamp is turned ON. ~ Peak detection (white color is detected by the shading correc-

tion plate) ~ The exposure lamp is turned OFF.

• Set number “1” and “READY (WARMING UP)” are displayed.

(2) Pre-running operation

The pre-running operation is started when the temperature of the fuser roller reaches a certain

temperature.

• The fuser roller is rotated.

• The drum is rotated.

~ The main motor is turned ON.

• Initialization of laser optical system

~ The polygonal motor rotates at a low speed.

• Initialization of feeding system

~ Cassette trays go up.

• The pre-running operation is stopped after five seconds.

(3) When the temperature of the fuser roller becomes sufficient for fusing:

• Set number “1” and “READY” are displayed.

DP4500/3500 GENERAL OPERATION 4 - 2 December 2000 © TOSHIBA TEC

4.2.2 Standby state (ready for copying)

• Keys on the control panel operable

• When no key is pressed for a certain period of time:

~ Set number “1” and reproduction ratio “100%” are displayed. The copier returns to the normal

standby state.

4.2.3 Cassette feed copying

(1) Press START key

• “READY” changes to “COPYING”.

• The exposure lamp is turned ON.

• The scanner motor is turned ON n carriages -1 and -2 move forward.

• The main motor and exit motor are turned ON.

~ The drum, fuser unit, developer unit and exit roller are driven.

(2) Cassette paper feeding

• The main charger, developer bias and discharge lamp are turned ON. The fans rotate at high speed.

Feed clutch is turned ON.

~ The pickup roller, feed roller, separation roller and transport roller start to rotate.

• Paper reaches the upper feed sensor.

~ The upper feed sensor is turned ON.

• Paper reaches the registration roller.

~ The registration sensor is turned ON and aligning is performed.

• The feed clutch is turned OFF after a certain period of time.

(3) After the carriage operation:

• The registration clutch is turned ON after a certain period of time n paper is transported to the

transfer section.

• The copy counter operates.

(4) After the registration clutch is turned ON:

The transfer charger is turned ON after a certain period of time.

(5) Completion of scanning

• The scanner motor is turned OFF.

• The exposure lamp is turned OFF.

• The registration clutch is turned OFF (after the trailing edge of the paper passed the registration

roller).

• “READY (PRINTING)” is displayed.

(6) Paper discharging

• The exit sensor detects the trailing edge of the paper.

• The main charger, developer bias and discharge lamp are turned OFF.

• The main motor and exit motor are turned OFF.

• The drum, fuser unit and developer unit are stopped. The fans return to the standby rotation.

• “READY” is displayed and the copier enters the standby mode.


Timing in case of copying one A4 sized sheets fed from the upper cassette

500

0 6 18

246 36

6

1306

2316

1284

039

08

022

813

9823

94 2278

3378

4156

4296

042

96

2280

2246

2066

402

154

458

1658

1714

154

0

4156

1710

2296

1000

1500

2000

2500

3000

3500

4000

4500

5000

Sca

nner

m

otor

Exp

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e la

mp

Mai

n m

otor

Upp

er c

asse

ttefe

ed c

lutc

h

Upp

er f

eed

sens

or

Reg

istr

atio

n se

nsor

Reg

istr

atio

n cl

utch

MV

DE

N s

igna

l

Mai

n ch

arge

r

Dev

elop

er b

ias

Dis

char

ge l

amp

Exi

t se

nsor

(ms)

fwd.

rev. – +


4.2.4 Bypass-feed copying

(1) Insert some sheets of paper into the bypass tray.

• The bypass sensor comes ON.

~ “READY FOR BYPASS FEEDING” is displayed.

• The carriages move to the home position.

(2) Press START key

• “READY FOR BYPASS FEEDING” changes to “COPYING”.

• The exposure lamp comes ON.

• The scanner motor ON n Carriages -1 and -2 move forward.

• The main motor and exit motor are turned ON

~ The drum, fuser unit, developer unit and exit roller are driven.

(3) Bypass feeding

• The main charger, developer bias and discharge lamp are turned ON. The fans rotate at high speed.

• The bypass feed clutch is turned ON.

~ The bypass pickup roller and feed roller start to rotate.

~ The bypass pickup roller is lowered.

• Aligning operation

• Paper reaches the registration roller.

• The bypass feed clutch is turned OFF after a certain period of time.

(4) Hereafter, the operations (3) through (6) of “4.2.3. Cassette feed copying” are repeated.

4.2.5 Interruption copying

(1) Press the INTERRUPT key

• LED “INTERRUPT” is lit.

• Copying operation in progress is temporarily stopped, and the carriages -1 and -2 return to appropriate

positions.

• “JOB INTERRUPTED JOB 1 SAVED” is displayed.

• Automatic density and reproduction ratio 100% are set. The set number remains the same.

(2) Select the desired copy condition.

(3) After the interruption copying is finished:

• “PRESS INTERRUPT TO RESUME JOB 1” is displayed.

• LED “INTERRRUPT” goes OFF by pressing the INTERRUPT key, and the copier returns to the

status before the interruption.

• “READY TO RESUME JOB 1” is displayed.

(4) Press START key

The copying operation before the interruption is resumed.


4.3 Detection of AbnormalityWhen something abnormal occurs in the copier, the symbols corresponding to the type of abnormality are

displayed.

4.3.1 Types of abnormality

A) Abnormality cleared without turning off the door switch.

(1) Add paper

(2) Paper misfeed in bypass

B) Abnormality not cleared without turning off the door switch.

(1) Misfeed in copier

(2) Add toner

(3) Developer unit not installed properly

(4) Dispose of used toner

C) Abnormality not cleared without turning off the main switch.

(1) Call for service

4.3.2 Description of abnormality

A-1) Add paper

[In case of the copier cassette or PFP cassette] (When cassette is not installed)

Cassette not detected

Cassette is not installed

or

Cassette is installed but

there is no paper in it:

n No paper

x

A signal is sent to the control circuit.

x

Cassette in question flashes on the control panel.

x

START key is disabled.

[In case of the copier cassette, PFP cassette or LCF cassette] (When cassette is installed)

Based on the combination of the tray-up motor movement and the state of the tray-up sensor and

paper-empty sensor, the CPU detects the presence/absence of paper.


• When the power is turned ON or the LCF cassette is inserted (when the power is turned ON or copier

cassette/PFP cassette is inserted),

LCF performs initialization.

x

Detects the presence/absence of paper

Tray-up motor ON ~ The tray goes up

At this time, the tray-up sensor and LCF empty sensor are OFF.

bbn If the tray-up sensor is not turned ON in a fixed time, the tray is in abnormal condition.

n “Add paper” is displayed regardless of presence/absence of paper.

qax

Cleared by turning ON and OFF the power

bbn Tray-up sensor is turned ON in a fixed time.

~ The tray-up motor stops.

At this time, if the empty sensor is ON: It is judged that there is paper.

At this time, if the empty sensor is OFF: It is judged that there is no paper.

x


• When paper in the cassette gets short during copying,

The tray-up sensor is turned OFF.

n The tray-up motor is turned ON. n The tray goes up.

The tray-up sensor is turned ON. n The tray-up motor is stopped.

• The empty sensor is turned OFF during the copying in spite of the tray-up sensor being ON

It is judged that there is no paper.

x


x

The copying operation is stopped.


A-2) Paper misfeed in bypass ( )

• During the bypass feeding

The bypass feed clutch is turned ON.

x

The registration sensor is turned ON.

* The registration sensor is not turned ON in a fixed time (E12).

x

Bypass misfeeding

x

The bypass misfeeding symbol ( ) is displayed.

x

The copying operation is disabled.

x

Solution: The bypass paper sensor is turned OFF by removing the paper from the bypass tray.

B-1) Misfeed in copier ( )

• The exit sensor detects that the leading edge of paper is jamming.

x

The registration clutch is turned ON.

x1.056 sec.

The exit sensor is turned ON.

If the exit sensor is not turned ON even though

1.056 seconds have elapsed,

x

Paper jam (E01) n The copying operation is stopped.

• The exit sensor detects that the trailing edge

of paper is jamming.

x

The registration clutch is turned OFF.

x 1.116 sec.

The exit sensor is turned OFF.

If the exit sensor is not turned OFF even though

1.116 seconds have elapsed,

x

Paper jam (E02) n The copying operation is stopped.

• Immediately after the power comes ON

x

Any of the sensors to detect a paper which is tranported on the transport path detects the presence

of a paper (ON).

x

Paper jam (E03)

Registration clutch

Exit sensor

Timer0

Paper jam (E01)

ON

ON

1.056sec.

Registration clutch

Exit sensor

Timer0

Paper jam (E02)

ON

OFF

1.116sec.


• The front cover is opened during copying.

x

Paper jam (E41)

• The registration sensor detects that the leading edge of paper is jamming.

x

The registration sensor is not turned ON in a fixed time after the leading edge of paper passed the

transport roller.

x

Paper jam (E12, E20, E21, E30, E33 and E3C)

• When paper is fed from the ADU:

The registration sensor is not turned ON in a fixed time after the ADU clutch is turned ON.

x

Paper jam (E11)

• When paper is transported into/from ADU:

The ADU entrance/exit sensors do not detect the paper at the fixed timing.

x

Paper jam (E51 or E52)

• When paper is fed from the main unit or PFP cassette:

The registration sensor is not turned ON in a fixed time after the feed clutch is turned ON.

x

Paper jam (E22, E31, E32, E34~E36, E3D and E3E: Error code defers depending on the paper

source.)


B-2) Add toner ( )

The toner density becomes low.

x

The auto-toner sensor detects the absence of the toner.

x

Control circuit n “Add toner” displayed: the copying operation disabled.

Solution: Open the front cover and replace the toner cartridge with a new one.

Toner supplied n copying operation enabled.

B-3) Developer unit not installed properly

The connector of the developer unit is disconnected.

x

“Developer unit not installed” displayed.

Solution: Connect the connectors of the developer unit and close the front cover.

B-4) Dispose of used toner ( ).

• The toner bag becomes full of toner.

x

The toner recovery auger moves towards the rear of the copier: the toner bag full detection sensor is

turned ON.

x

“Dispose of used toner” is displayed.

• When the toner bag full detection sensor is turned ON.

x

Copying operation is disabled after the sheet which is being copied is discharged in the paper

receiving tray.

Solution: Replace the toner bag with a new one.

C-1) Call for service

An error code is displayed instead of the set number by pressing the CLEAR/STOP key and “8” key

simultaneously when “Call for service” is flashing.

Refer to the error code table in the Service Handbook.


4.4 Flow Chart4.4.1 Immediately after the power is turned ON

YES

YES

NO

A B

NO

NO

NO

NO

NO

NO

NO

NO

YES

YES

YES

YESCall for service

YES

YES

YES

“E03”

“C26”

“C27”“C28”

Main switch ON

DC power ON

Restart

Cover is open?

IH coil ON

Paper jam

Registration sensorON? Scanner motor ON

Home positiondetected?

Peak detected?

2.5 seconds elapsed?

Call for service

Exit sensorON?

ADUentrance/exit sensors

ON?

Upper feedsensor ON?

Lower feedsensor ON?


YES

YES

NO

A

B

Main motor ONPolygonal motor ONTray-up motor ON

Fuser rollerreached ready

temp.?

Main motor OFF

READY

YES

Call for service

YES

Call for service

IH coil broken?

YES

Polygonal motor in abnormal

condition?

Call for service

NO

NO

NO NO

“C41”“C43”

“C44” “CA1”

YES

IH error

Call for service

NO

“C47”“C48”“C49”

Thermistorbroken?

Temperature of thefuser roller ready for pre-running?


4.4.2 Automatic paper feed copying

OK

NO

NO

Main motor ONExit motor ON

Developer bias ONMain charger ONDischarge lamp ON

Remaining set number=0?

Press START key

Transport system control

YES

YES

YES

NO

NO

NG

Laser ON

Remaining setnumber=0?

Processing systemcontrol completed

H-SyncOK?

Processing system control

Call for service

Polygonal motornormal rotation?

“CA1”

Transfer charger ON

Transfer charger OFF

Feed clutch ON

Feed clutch OFF

Registration clutch ONCounter ON/OFF

Registration clutch OFF

Call forservice

Laser OFF

C

Scanner system control

Exposure lamp ON

Carriages move forward

Carriages stopped

Exposure lamp OFF

Carriages move backward

Carriages stopped

Scanner system control completed

“E01”

YES

“CA2”

Paper jam

Exit sensordetected leading edge of paper?


OK

NG

C

Main charger OFFDischarge lamp OFFDeveloper bias OFFExit motor OFF

Standby

Drum rotation reversed

Main motor OFF

Paper jam

“E02”

Exit sensordetected trailing edge of paper?

December 2000 © TOSHIBA TEC 5 - 1 DP4500/3500 DISPLAY UNIT

5. DISPLAY UNIT

5.1 Control Panel and Display PanelThe display unit consists of key switches and touch-panel switches to operate the copier and select

various modes, and LEDs and an LCD to display the state of the copier or the messages.

When the operator’s attention is reguired, graphic symbols appear with messages explaining the condition

of the copier in the LCD panel.

Control panel

PRINTER/NETWORK COPY FAX

1

1

2 3

4 5 6

7 8 9

0JOB STATUS

START

CLEAR/STOP

FUNTION CLEAR

INTERRUPT

MAIN POWER

POWER

MONITOR//PAUSE

MEMORY RXDATAERROR

ABC DEF

JKLGHI MNO

TUVPQRS WXYZ

2

C/

FC

HELP

DP4500/3500 DISPLAY UNIT 5 - 2 December 2000 © TOSHIBA TEC

5.2 Items Shown on the Display Panel

Fig. 5.2-1

Fig. 5.2-2

CA

E

I

D

FK

G

J

H

B


No. Message

1 WAIT WARMING UP

2 READY(WARMING

UP)

3 READY

4 COPYING

5 Saving energy

- press START

6 Place next original

Press START to

copy

7 -

8 READY (PRINTING)

9 READY

(ADD PAPER)

10 READY

(FINISHER FULL)

11 READY

(HOLE PUNCH

DUST FULL)

State of copier

Scanner warming up

- Displayed when the power is turned ON un-

til the copier becomes ready to start scan-

ning.

Ready for scanning

- The copier is ready for scanning and waiting

for operator to select the copying conditions.

- Returns to default setting if no key is pressed

within 45 seconds.

Ready for copying

- The copier is ready for copying and waiting for

the operator to select the copying conditions.

- Returns to default setting if no key is pressed

within 45 seconds.

The original is being scanned

- Displayed by pressing the START key.

The copier is in the energy saver mode

Ready for the next original

- Displayed by pressing the [Next original;

YES] icon.

Power is OFF

- Nothing is displayed in the display panel.

- Power LED is lit in red.

Ready for scanning


for the operator to select the copying conditions.

Background printing is in progress

Ready for scanning



Paper in the cassette has run out during printing

Ready for scanning



The finisher is full of paper

Ready for scanning


for operator to select the copying conditions.

The punching dust box is full

Note

- The set number “1” and the repro-

duction ratio “100%” are displayed

when the power is turned ON.

- The set number “1” is displayed. Press

the digital key to change the number.

- The number is reset to “1” by pressing

the CLEAR/STOP key.

- Bypass feed copying is enabled.

- The set number “1” is displayed. Press

the digital key to change the number.

- The number is reset to “1” by pressing

the CLEAR/STOP key.

- Bypass feed copying is enabled.

- After scanning is completed, the copier

becomes ready for the next scanning.

- Can be cleared by pressing the

START key or FUNCTION key.

- Displayed for SADF and manually

placed originals.

- Press the POWER key.

- Since background printing is in

progress, the scanned image is not

output immediately.

- Printing is resumed by adding paper

to the cassette.

- Printing is resumed by removing

paper from the finisher.

- Printing is resumed by removing

punching dust from the dust box.

5.2.1 Display during normal copying


No. Message State of copier Note

12 READY

(SADDLE STITCH

TRAY FULL)

13 READY

(SET CORRECT

CASSETTE)

14 READY (ADDING

TONER)

15 READY (INSIDE

TRAY FULL)

16 READY (CHECK

STAPLER)

17 READY (CHECK

SADDLE STITCH

STAPLER)

18 READY (USE

GENUINE TOSHIBA

TONER)

19 ENTER DEPART-

MENT CODE

Ready for scanning



The saddle stitcher is full of paper

Ready for scanning



Cassette not installed during printing

Ready for scanning

- The copier is ready for scanning and

waiting for the operator to select the

copying conditions.

The toner is being added from the cartridge

Ready for scanning


for the operator to select the copying

conditions.

The receiving tray is full of papers

Ready for scanning

- The copier is ready for scanning and waiting for

the operator to select the copying conditions.

The finisher unit runs out of the staples.

Ready for scanning



copying conditions.

The saddle stitcher unit runs out of the

staples

Ready for scanning



copying conditions.

Toner other than Toshiba’s has been used

The copier is waiting for the operator to

enter the department code.

- Displayed when the department manage-

ment function has been used.

Printing is resumed by removing paper

from the saddle stitcher unit.

- Printing is resumed by changing

the setting for cassette selection,

then pressing the START key.

- Printing is resumed automatically

when the toner supply is completed.


when the paper is removed from

the receiving tray.


when the staple cartridge is

replaced with a new one.


when the staple cartridge is


The display is made to disappear by

using the toner provided by Toshiba.

The copier becomes ready to start

copying when the correct depart-

ment code is entered.


No. Message

20 Add paper

21 Add toner

Press HELP/INFO

22 Set key copy

counter

23 Paper misfeed in

bypass

24 Misfeed in copier

Press HELP/INFO

25 Misfeed in copier

Press HELP/INFO

26 Misfeed in doc.

feeder

Press HELP/INFO

27 Misfeed in finisher

Press HELP/INFO

28 Misfeed in duplexer

Press HELP/INFO

29 Call for service

30 Time for periodic

maintenance

31 CHECK PAPER IN

LCF

32 Dispose of used

toner

Abnormal state and indication in display panel

Paper run out [Fig.5.2-1 A]

- The cassette with no more paper flashes.

Toner run out [Fig.5.2-2 B]

- The toner cartridge is empty.

- The message is displayed and the copier is

stopped.

Key copy counter not installed [Fig.5.2-1 C]

- The key copy counter was pulled out when

copier was ready for scanning.

- When the key copy counter is pulled out af-

ter the START key is pressed, the copier is

stopped as soon as the copying is finished.

Bypass paper jam [Fig.5.2-2 D]

- Paper jam at the bypass tray

Paper jam in the copier [Fig.5.2-2 E]

Misfeeding of cassette paper [Fig.5.2-2 F]

- Paper fed from the cassette does not reach

the feed sensor in a fixed time.

Original jam [Fig.5.2-2 G]

- Original jamming in ADF

Paper jam in the finisher [Fig.5.2-2 H]

Paper jam in the ADU [Fig.5.2-2 I]

Motors, sensors, switches, etc. do not work

properly. [Fig.5.2-2 J]

PM cycle

- Time for maintenance

- Copying is possible

Paper misloading in LCF

- Paper is not stacked up correctly.

Toner bag full

- The toner bag is full of used toner.

The copier stops its operation. [Fig.5.2-2 K]

Solution

- Add paper to the cassette.

- Select a different cassette.

- Replace the toner cartridge and close

the front door.

- Insert the key copy counter (option).

- Remove the paper from the bypass

tray.

- Press the HELP/INFO key and re-

move the paper following the mes-

sages shown on the display panel.




- Open the jam-access cover and ADF

unit to remove the original.







- Turn OFF the power and solve the

problem, then turn ON the power again.

- Maintenance and inspection are per-

formed by a qualified service techni-

cian.

- Set the paper correctly.

- Replace the toner bag with a new

one and close the front cover.

5.2.2 Display in the abnormal condition


5.3 Relation between Copier State and Operator’s ActionO

pera

tion

STA

RT

C/S

Dig

ital

Cas

sette

INTE

RR

UPT

PO

WE

RB

ypas

sTo

uch

FUN

CTI

ON

CO

ND

ITIO

N

Sta

te o

f co

pier

key

key

keys

sele

ctio

nke

yke

yfe

edin

gp

an

el

key

key

Sca

nner

war

min

g up

--

--

Prin

ter

war

min

g up

Rea

dy f

or c

opyi

ng

Pri

ntin

g

Sca

nn

ing

--

--

--

--

Pap

er r

un o

ut

Tone

r em

pty

Key

cop

y co

unte

r no

t in

sert

ed-

(opt

iona

l)

Pap

er m

isfe

ed i

n by

pass

cop

ying

--

--

--

--

--

Pap

er ja

mm

ed in

side

the

mac

hine

--

--

--

--

--

Ser

vice

cal

l in

dica

ted

--

--

--

--

--

Rea

dy f

or i

nter

rupt

cop

ying

--

In e

nerg

y sa

ver

mod

e-

--

--

--

Pow

er O

FF

--

--

--

-

: O

pera

tion

enab

led

-

: Ope

ratio

n di

sabl

ed


5.4 Description of Operation5.4.1 Dot matrix LCD circuit

(1) Structure

The DSP-LCD-320 is an STN blue mode transmissive type LCD with a 320 x 240-dot display capacity. It

consists of a driver LSI, frame, printed circuit board, and lateral type CFL backlight.

*STN:Super Twisted Nematic

(2) Block diagram

(320 x 240)

IC1

IC5

XSCL

UD0UD1UD2UD3

WF

LP

VDDGNDV0VEE

Power supply

LCDEN

IC6

IC7

IC2

LCD PANEL320 x 240 DOTS

IC3 IC4

80

80

80

80 80 80 80


(4) Data Transmission

(3) LCD drive operation

The following describes the drive operation to display the message “READY”.

(a) The SYS CPU requests the PROM

data to display “READY”.

(b) The PROM outputs data to display

the message to the SYS CPU.

(c) The SYS CPU writes the data to be

displayed on the LCD into the RAM.

(d) The LCD controller/driver reads the

display data from the RAM, and out-

puts the data to the LCD.

PROMCPU

RAM

LED

LED LCD KEY CPU

PWA-F-DSP-300

PWA-F-SYS-300

GA

LCD

SYS(a)

(b)(c)

(c)

(d)

(d)

LOAD

FRAME

LOAD

240 1 2 240

CP x(320/4) pulses

1 2 240

1/tF1/tF

1 2

FRAME

D0-D3

CP

controller

driver

PWA-F-SYS-320

PWA-F-DSP-320

Key switchesand

touch panel


LDON0"L"

"L" 17D7

Q3

IC8(7932)

R6(COPY)

5VL

LED5

G

5.4.2 LED display circuit

(1) Method of LED display

ex) Displaying “COPY” .

The transistor is turned ON when the LDON 0 signal becomes “L” level.

Also, when IC8-17pin (D7) changes to “L”, the current flows from 5VL via the transistor to LED5 (“COPY”)

to turn ON LED5 (“COPY”).

Current

Conditions to turn ON the LED

(a) The transistor (Q3) connected to the LED anode is ON.

(b) The output from the cathode side of the LED is “L” level.

The LED is turned ON when (a) and (b) are satisfied.


(5) Remove 4 screws and take off the LCD board.

(6) Remove 11 screws and take off the KEY board.

5.5 Disassembly and Replacement[A] Control panel

(1) Take off the front side right cover, front top cover

and control panel lower cover.

(2) Disconnect one connector and remove 5 screws.

Take off the control panel unit.

(3) Remove 6 screws and take off the 3 brackets.


Release 6 lock supports and take off the DSP

board.

Control panel unit

Connector

Lock support

DSP board Lock support

KEY board LCD

December 2000 © TOSHIBA TEC 6 - 1 DP4500/3500 IMAGE PROCESSING

6. IMAGE PROCESSING

6.1 General DescriptionThe following diagram shows the process from scanning of the original to data writing on the photoconduc-

tive drum surface of the digital copier.

ASIC stands for “Application Specific IC”, meaning an IC designed for a particular use.

The followings are the boards used for image processing.

Board Number of ASIC Function

CCD board

(PWA-F-CCD-320)1

LGC board1

(PWA-F-LGC-320)

Image processing/writing control

section[LGC]

Image processing section

Photocon-ductivedrum

System board[SYS]

Scanningcontrol section

[SLG]

Scanning section

Original

Original glass

Scanning/image process-

ing section[CCD]

Semicon-ductive laserelement

Laser drive board[LDR]

Writing section

Polygonal motordrive board

[POL]

High-quality image processing, image memory editing, editing

processing, gamma correction, gradation processing, external

output system interface

Smoothing processing, external input system interface, image area

control, laser related control

DP4500/3500 IMAGE PROCESSING 6 - 2 December 2000 © TOSHIBA TEC

6.2 Image Processing Circuit6.2.1 General description

The image of an original placed on the original glass is scanned by the carriage. The CCD (Charge Coupled

Device) reads the optical image signals and converts them into the electrical signal. The electrical signals

then undergo the analog-to-digital conversion and are changed into digital signal. The shading correction

(correction of variance in CCD elements and the light source) is performed on the digital signal, then it is

output as an image signal from the scanning section.

The image processing section inputs this image signal from the scanning section and applies various

types of image processing on it, then sends the output result to the writing section.

Images are processed by the CCD board (PWA-F-CCD-320), SLG board (PWA-F-SLG-320) and LGC

board (PWA-F-LGC-320) in this copier.

(1) Image processing circuit on the CCD board

One image processing ASIC is mounted on the CCD board, realizing the following functions:

<Functions>

High-quality image processing, image memory editing, edit processing, gamma correction,

gradation processing and external output system interface

(2) Image processing circuit on the LGC board

One image processing ASIC is mounted on the LGC board, realizing the following functions:

<Functions>

Smoothing processing, external input system interface, image area control and laser related control


6.2.2 Configuration

The following diagram shows the image processing section of this copier.

Fig. A. Configuration of the image processing section

CCD board(PWA-F-CCD-320)

CCD

A/D conversion

Image processing ASIC for Scanner section

Shading correctionHigh-quality image processing

Image memory editingEditing processingGamma correction

Gradation processingExternal output system interface

SLG board(PWA-F-SLG-320)

SYS board(PWA-F-SYS-320)

Sorting, group copy, magazinecopy, single side reduction/con-junction, double side reduction/conjunction, image composition,date insertion, sheet insertionmode, etc.

Scanner CPU

Scanning control

LGC board(PWA-F-LGC-320)

Image processing ASIC for Printer sction

Smoothing processingExternal input system interface

Image area controlLaser related control

Main CPU

Laser writing control

Laser drive board(PWA-F-LDR-320) : Image data flow

Image processingsection

Laser drive


6.3 CCD Board (PWA-F-CCD-320)6.3.1 Features

(1) The image processing ASIC on the CCD board is controlled by the CPU on the SLG board.

(2) The image processing ASIC on the CCD board realizes the following functions:

• High-quality image processing

• Image memory editing

• Editing processing

• Gamma correction

• Gradation processing

• External output system interface

6.3.2 Functions of image processing circuit

An image processing ASIC mounted on the CCD board realizes the following functions:

(1) High-quality image processing

(a) Range adjustment

This function converts the image signals into a density range, and adjusts it so that it is suited to each

original image. It is possible to eliminate undesirable background density when an original with a certain

level of density on the background, for example a newspaper, is copied.

<Example>

Histogram

Dynamic range

Sm

all

No.

of p

ixels

Larg

e

Low Density

High Low Density

High

Text

Back-ground

After rangeadjustment

Extended dynamic range

Sm

all

No.

of p

ixels

Larg

e


0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9

(b) Filtering

This function is enabled by a low-pass filter circuit and a high-pass filter circuit.

• Low-pass filter circuit

This circuit removes image noise and electrical noise, decreases moire, and realizes high

reproductibility of original by applying an averaging operation on the image signal of the targeted

pixel and those of the pixels positioning next to it.

<Example> The density of the targeted pixel position is “x”. The density of the pixel positions at

the front and back of the targeted pixel are “a” and “b” respectively, “x” is converted to

“x’” through low pass filtering.

When the matrix is (3 x 1):

The above averaging operation is performed for all the pixel positions to accomplish the high

reproducibility of the original.

The following is when low pass filtering is applied on the primary scanning pixel.

(b) High-pass filter circuit

The change of the density at the character outline becomes smooth when an original, such as text,

with a great difference in density between the pixels placed next to one another is optically scanned

and output from the CCD. This is caused by the characteristic of the lens and other factors. In this

copier, the process such as the edge enhancement, is applied on the targeted pixel and the pixels

around it to eliminate this phenomenon and realize high reproductibility of the original.

Density

After low-pass filtering

Primary scanning pixel positions

a + b + x3

x’ =

Original

Image signal

After correction

Low contrast area

Solid black area

Density

Primary scanning pixel positions

a x b


(2) Image memory editing

This function performs editing such as enlargement/reduction, mirror imaging, etc. using the line memory.

Pixel data for one line in the primary scanning direction are stored in the line memory and the memory

is renewed at each line.

(a) Enlargement/reduction

The enlargment/reduction is accomplished by using the line memory control function in the process

of the image processing operation.

<Example> Enlargement

<Example> Reduction

(b) Mirror imaging

This is accomplished by reading and outputting data from its end.

(3) Edit processing

This function performs trimming, masking and negative/positive reversing.

(a) Trimming

Using rectangular area signals, the image signals inside the rectangular area are left and the

other image signals outside the area are eliminated.

(b) Masking

Using rectangular area signals, the image data inside the rectangular area are erased.

(c) Negative/positive reversing

This function reverses the entire data from negative to positive or vice versa.

1100%

200%

2 3 4 5 6 7 8 9 10

1 1 2 2 3 3 4 4 5 5

1100%

50%

2 3 4 5 6 7 8 9 10

1 3 5 7 9


(4) Gamma correction

This function corrects the input/output characteristics of the scanner/printer and adjusts the image

signals so that their input/output characteristics match with the copy mode.

(5) Gradation processing

This function works for genuine reproduction of halftone image such as photographs.

(6) External output system interface

This function controls the output of the output interface between the CCD board and the SYS board

(PWA-F-SYS-320).


6.4 LGC Board (PWA-F-LGC-320)6.4.1 Features

(1) The image processing ASIC on the LGC board is controlled by the CPU on the LGC board.

(2) The image processing functions of the LGC board realizes the following functions:

• Smoothing processing

• External input system interface

• Image area control

• Laser related control

6.4.2 Functions of image processing circuit

An image processing ASIC mounted on the LGC board enables the following functions:

(1) Smoothing processing

This function removes jagginess and smoothes character outline of the text images input from the

external input system interface, and output them.

(2) External input system interface

This function controls the input interface between the LGC board and the SYS board (PWA-F-SYS-

320).

(3) Image area control

This function sets the effective image area of four directions for the image to be output.

(4) Laser related control

This function controls the APC (Auto Power Control).


6.5 Scanning SectionLight reflected from original surface is directed to the CCD which performs the photovoltaic conversion,

and the optical image data are converted into an electrical signal. This analog signal undergoes the A/D

conversion processing and is changed into a digital signal. The signal then undertakes various corrective

processes necessary for image formation.

(1) Photovoltaic conversion

The CCD elements convert the optical signal into electrical signal. ( Chapter 7.6.1)

(2) Signal amplification

Amplifies the electrical signals converted in the CCD.

(3) A/D conversion

Converts the analog signal into the digital signal.

(4) Shading correction

The shading correction is applied on the signal read by CCD. ( Chapter 7.6.2)

6.6 Writing SectionThe image signal processed by the LGC board is processed by the ASIC for writing control and laser drive

board. The laser is controlled based on the signal, writing data on the drum.

(1) Setting the effective image area........................ • Top, bottom, left and right margins

(2) Horizontal synchronization signal (H-Sync) ....... • The reference clock signal in the printer section

clock generation section synchronized with the H-Sync and its signal.

(3) Laser drive section ........................................... • ON/OFF control of the semiconductive laser and

APC (Auto Power Control) control.

CCDSignal

amplificationA/D

conversionShading

correction Next stage

December 2000 © TOSHIBA TEC 7 - 1 DP4500/3500 SCANNER

Exposure lamp

Carriage-2

Reflector Carriage-1 Original glassRail for carriage-1 Drive pulley

LensCCD sensor CCD board SLG board

Rail for carriage-2

7. SCANNER

7.1 FunctionIn the scanning section of this copier, the surface of an original is irradiated with a direct light and the

reflected light is led through mirrors, lens and slit to the CCD where the optical-to-electrical conversion is

performed, converting the optical image data into an electrical signal. This analog signal is changed to a

digital signal, and then undertakes various corrective processes necessary for image formation. After that,

an arithmetic operation is performed on the digital signal, which is then sent to the data writing section.

Shading correction plate

DP4500/3500 SCANNER 7 - 2 December 2000 © TOSHIBA TEC

7.2 ConstructionThe construction and purpose of the scanning system are described in this section.

(1) Original glass

This is the glass on which originals to be copied are placed. The light from the exposure lamp is irradiated

to the original through this glass.

(2) Carriage-1

The carriage-1 consists of the exposure lamp, lamp inverter, reflector, mirror-1, etc. It is driven by the

scanner motor and scans the original on the glass.

Mirror-1

a. Exposure lamp

This lamp is the light source to irradiate the original on the glass (one 20W Xenon lamp).

b. Lamp inverter

Controls lighting of the Xenon lamp.

c. Reflector

This is a plate to direct the light from the exposure lamp efficiently to the surface of the original on the

glass.

Lamp inverterReflector

OriginalOriginal glass

Exposure lamp

Reflector

Mirror-1


d. Mirror-1

This mirror directs the light reflected from the original to the mirror-2 described later.

(3) Carriage-2

The carriage-2 consists of mirror-2, mirror -3, etc. and directs the reflected light from the mirror-1 through

mirrors-2 and -3 to the lens.

This carriage is driven by the scanner motor as the carriage-1, at half the scanning speed of carriage-1 (the

scanning distance is also half that of carriage-1).

Mirror-2

Mirror-3


(4) Lens unit

The light reflected from mirror-3 is led to the CCD placed at the focal point of the lens which is fixed in

position.

(5) CCD drive PC board

Processes such as the signal amplification, signal integration, A/D conversion and shading correction are

applied on the electrical signal which was converted by the CCD.

(6) Automatic original detection sensor

The size of the original placed on the glass is instantly detected using the automatic original detection

sensors (APS sensor) fixed on the base frame without carriage-1 having to move.

CCD drive PC boardLens unit


Carriage-1Carriage wire Scanner motor Pulley for carriage-2ø20

Idler pulleyø20

Wire winding-up pulley/motor speed-reduction pulley

ø39/2GT-Z63Carr iage-2CRG2

Idler pulleyø20

Motor pulley2GT-Z21

7.3 Description of Operation7.3.1 Scanner motor

(a) Scanning an original placed on the original glass

This motor drives the carriages-1 and -2 through the timing belt and carriage wire. The scanner motor

first drives carriages-1 and -2 to their respective home positions. The home positions are detected

when carriage-1 passes the home position sensor. When the START key is pressed, both carriages

start to move and scan the original on the glass.

(b) Scanning an original placed on the ADF

Carriage-1 stays at the shading position during the shading correction, and at the scanning position

during the scanning operation.


7.3.2 Two-phase motor drive circuit (fixed-current type)

The scanner motor is driven by the stepping motor driver IC-STK672-080 (IC1) with the unipolar fixed

current chopper method.

15141312111098

67

EN

AB

LEMol

RE

SE

T

M3

CLO

CK

CW

B

M2

M1

Vcc

2V

ref

AA

BB

BB

PG

SU

B

54

32

1

Exc

itatio

nm

ode

setti

ng

Switc

hing

pul

seO

N/O

FF d

etec

tion

Exc

itatio

nst

atus

mon

itor

CR

osc

illat

ion

Pha

seco

unte

r

Gen

erat

ion

ofre

fere

nce

clock

PWM

cont

rol

Gen

erat

ion

of p

hase

excit

atio

n sig

nal

Gen

erat

ion

of p

seud

osi

ne w

ave

Switc

hing

curre

ntfra

ctio

n ra

tio


The motor is rotated by setting the number of pulses.

* The internal circuit of the motor driver works when the first pulse

becomes ON and the last pulse becomes OFF.

The direction of the motor rotation is determined by the setting level

of signal

“H”…Clockwise direction (as seen from the output shaft)

“L”…Counterclockwise direction (as seen from the output shaft)

Note: When SCNMD3-0A is “L”, do not change the rotation direction

within 6.25µs before the first pulse of the SCANCK-0A becomes ON

and after the last pulse becomes OFF.

“H” …Normal operation (The motor has been excited.)

“L”…Excitation drive output is forcibly shut OFF (the motor has not

been excited).

Motor wire current value is set in the range of 0 to 2.25 (A)/phase by

applying the analog voltage 0 to 5 (V).

Sets the excitation mode.

Note: Do not change the setting wihin 5µs after the first pulse be-

comes ON and the last pulse becomes OFF.

Internal circuit of the driver is initialized by setting the motor to “L”

level (pulse interval: 10µs or more).

The motor drive circuit is automatically reset when the power is

turned ON.

SCNCK-0A CLK input Input

SCNDR-0ASets the direction

Inputof motor rotation

SCNEN-0ACuts OFF the

Inputdrive output

SCNREF-0AVoltage to set value

Inputfor the motor current

SCNMD1,2,3 Sets the exicitationInput

-0A mode (1)–(3)

SCNRST Reset Input

B10+24V

SCN-MOT

PWA-F-SLG PWA-F-SDV

+24V

DG

GND

VDD

DG

B9

B8

B7

B6

B5

1

2

3

4

5

6

6

5

4 3 2 1

B4

B3

B2

B1

A4

A3

A2

A1

13

J18J5

J19

11

8

7

6

5

4

3

2

1

9

10

12

14

+24V

DG

SCNEN-0A

SCNDR-0A

SCNRST

SCREF-0A

SCNMD3-0A

SCNMD2-0A

SCNMD1-0A

SCNCK-0A

GND

VDD

DG

+24V

Circuit diagram

Input signals

Cut off output

Set motor rotationdirection

ResetVoltage to set value formotor current

Excitation mode setting (3)



CLK input


7.4 Control of Exposure Lamp7.4.1 General description

Control circuit of the exposure lamp consists of the following three blocks:

(1) Lighting device for the Xenon lamp (Inverter)

Turns the exposure lamp ON/OFF.

(2) CCD sensor circuit

This circuit works to the convert the reflected light amount from the original surface and the shading

correction plate to the electrical signals. The reflected light amount from the shading correction plate is

read to control the exposure amount.

(3) Image processing circuit

The output signals from the CCD are digitized and the image processing such as gamma correction

and shading correction is applied to them.

PWA-CCD

PWA-CCD

Image processingcircuit

A/D

PWA-SLG

Main CPUIC37

Construction of exposure lamp control circuit

Original Shading correction plate

Exposure lamp (Xenon lamp)

CCD sensor

Lighting devicefor Xenon lamp

(Inverter)

ScannerCPU


7.4.2 Exposure lamp

External electrode type Xenon fluorescent lamp is used as an exposure lamp in this copier.

(1) Structure

The fluorescer is applied to the in-

side surface of the lamp pipe (ex-

cept for a part which serves as an

opening) which is filled with the Xe-

non gas.

A pair of the external electrodes

covered by film with adhesive agent

is attached around the pipe.

(2) Behavior inside the lamp

The electron inside the pipe is led

to the electric field by applying volt-

age to the pair of the external elec-

trodes, and the discharge is started.

The electrons then flow and clash

with the Xenon atoms inside the pipe

to excite them and allow them to

generate ultraviolet rays. This ultra-

violet rays convert the fluorescer into

visible light.

(1)Electrode (2)Electron (3)Xenon atom (4)Ultraviolet ray (5)Fluorescer(6)Visible light (irradiated from the opening to outside the pipe)(7)Opening (8)Harness

PET film

Aluminum tapeelectrode

Adhesive agent

Glass valve

Fluorescer

Xenon gas

(1)(6)

(8)(7)

(5)

(2) (4)

(3)


7.4.3 Control circuit for the exposure lamp

Working conditions

WDTOUT-0 WDTEN-0EXPON-0

+5VSW Q2 Xenen lamp State of copier(Lamp drive signal)

H H H ON OFF OFFNormal operation

H H L ON ON ON

L X X OFF OFF OFFScanner CPU

overdriving

H L X OFF OFF OFF Call for Service

HCT00IC10 HCT00

IC10

HCT00IC10

P24

VDD

+5VSW

Q2: RN2401

R92: 330Ω

EXPON–0A

PWA–F–SLG–320

B

E

C

EXPON–0

WDTOUT–0

WDTEN–0P23

IC1

WDTOUTHC14IC9

ScannerCPU

Xenon lamp

Lightingdevice forXenon lamp


7.5 General Description of CCD Control7.5.1 Opto-electronic conversion

A CCD (charge-coupled device) is used to produce an electrical signal corresponding to the reflected light

amount from the original. The CCD is a one-chip opto-electronic conversion device, comprised of several

thousand light-receiving elements arranged in a line; each one of them is a few microns square.

This model is equipped with a CCD which has 7,450 light-receiving elements.

Each element of the light-receiving section consists of the semiconductive layers P and N. When the light

irradiates the element, the light energy produces a (-) charge in the layer P; the amount of the charge

produced is proportional to the energy and irradiating time. The charges produced in the light-receiving

section are then sent to the transfer section where they are shifted by the transfer clock from left to right as

shown in the figure below, and are finally output from the CCD. At this time, to increase the transfer speed

of the CCD, image signals in the even-number and odd-number elements are separated and output in

parallel via two channels.

7.5.2 Shading correction

Signal voltages read by the CCD have the following characteristics.

(1) Light source has variation in its light distribution.

(2) Since the light beam reflected from the original is converged using a lens, the light path is the

shortest at the center of the CCD and the longest at ends. This causes difference in the amount of

light reaching the CCD (i.e. the light amount is maximum at the CCD center, gradually decreases

toward ends).

(3) Each of the 7,450 elements varies in the opto-electronic conversion efficiency.

These variations need to be corrected and this correction is referred to as shading correction. Based on the

black and white data obtained in advance, a normalization process using the following formula is applied to

the raw image data to correct lighting variance and element variation of the image data.

I = k × (S — K)(W — K)

k : Coefficient

S : Image data before correction

K : Black data (stored in “black” memory)

W : White data (stored in “white” memory)

1 7447 7448 7449 74502 3 4

Transfer section

Light receiving section

Transfer section

Shift register

Transfer clock Light energy

layer N

layer P

Details of light receiving element

Transfer clock

[Principle of the opto-electronic conversion by CCD]


7.6 Automatic Original Size Detection CircuitThis circuit detects the size of original (standard sizes only) using the reflection type photosensors ar-

ranged on the base frame of the scanner unit.

7.6.1 Principle of original size detection

The reflection type photosensors are placed on the base frame of the scanner unit as shown in the Fig.

7.6.1. Each sensor consists of an infrared light emitting diode (LED) on the light emitting side, and a

phototransistor on the light receiving side.

When there is an original on the original glass, light beams from the LEDs are reflected by the original and

led to the phototransistors. This means that the size of the original is detected by checking which

phototransistors are turned on or are not.

Fig. 7.6-1

Fig. 7.6.2 Original size detection circuit

OriginalOriginal glass

[A4 Series]

APS-2APS-3

APS-4 APS-1

APS-5

[LT Series]Original glass

Original

APS-1

APS-6

APS-3APS-2

VDD

P8133

30

29

28

GND PWA-SLG

P96

P95

P94

APS-3

APS-2

APS-1

APS-6

Reflection type

photosensor

[LT Series][A4 Series]

VDD

P8133

32

30

29

28

GND PWA-SLG

P80

P96

P95

P94

APS-4

APS-3

APS-2

APS-1

APS-5

7.6.2 Process of original size detection

(1) When the copier is in the original size detection mode, the carriage-1 is set at its home position.

(2) When the platen cover is opened, the sensors receive the light reflected from the original and if one of

the matrix conditions shown in (4) for original sizes is satisfied, the size of the original is instantly

detected.

(3) The output signal from each sensor is input to the CPU on the scanner control PC board to determine

the size of the original.

Reflection type

photosensor


[A4 Series]

[LT Series]

Fig.7.6.3 Sensor detection points

ST LT

LG

LD

ST–R

LT–R

APS6

APS1

APS2

APS3

A5 B5 A4

B4

A3

A5–R

A4–R

B5–R

APS5

APS1

APS2

APS3

APS4


(4) Original size is determined by the combination of the presense/absence of signals which are output at

each detection point. The combination chart for size determination of A4 series and LT series are as

follows.

[A4 Series]

Size judgement APS-1 APS-2 APS-3 APS-4 APS-5

A3 0 0 0 0 0

A4 0 0 0 0 1B4 0 0 0 1 0

B5 1 0 0 1 1A4-R 0 0 1 1 0A5 1 0 1 1 1

B5-R 0 1 1 1 0A5-R 0 1 1 1 1

[LT Series]

Size judgement APS-1 APS-2 APS-3 APS-6

LD 0 0 0 0

LT 0 0 0 1LG 0 0 1 0

LT-R 0 0 1 1

ST 1 0 1 1ST-R 0 1 1 1

Code Output signal Original1 H Absent0 L Present

* When the platen sensor is OFF;• The following points are determined by output signals from the APS sensors

Size (The combination of the signals satisfy the above chart): Size is displayed on the control panel and an appropriate paper and reproduction ratio are selected.

Size retention (The combination of the signals do not satisfy the above chart): Retains the latest original size recognized (or no original state) until a new paper size is recognized.

No original (output from all the sensors are “1”.): Reproduction ratio and paper size are not selected.

• Size change is always observed and detected.• Carriage-1 stays at the standby position even if the reproduction ratio changes corresponding to the change of

the original size.* When the platen sensor is ON;

Retains the latest original size (or no original state) recognized right before the platen sensor is turned ONregardless of the state of the APS sensor output signals.


The reflection type photosensor is comprised of an infrared light emitting diode and a phototransistor. It

uses the pulse modulation to detect an original.

The light emitting diode is driven by a pulse having a 130-µsec cycle and an 8-µsec ON time. When the

phototransistor receives the same signal as this pulse, it is determined that there is an original. The

pulse modulation is performed inside the reflection type phototransistor.

About reflection type photosensor

130µsec LED

8µsec

Original

Phototransistor


7.7 Disassembly and Replacement[A] Original glass

(1) Take off the right top cover.

(2) Remove the original glass.

[B] Lens cover


(2) Remove the rear top cover.

(3) Remove 7 screws and disconnect one connec-

tor. Take off the lens cover.

[C] Automatic original detection sensor (APS sensor)

(C-1) A4 series


(2) Disconnect one connector and remove one

screw. Take off 5 APS sensors.

(C-2) LT series

(1) Remove the original glass and lens cover.


screw. Take off 4 APS sensors.

Original glass

Lens cover

APS sensor

APS sensor

Connector


[D] Exposure lamp

(1) Take off the left, rear and front top covers.

(2) Disconnect the connector of the exposure lamp

and release the harness from the clamp.

(3) Move carriage-1 to the position where both sides

of the frame are cut out.

Remove one screw and take off the exposure

lamp.

[E] Lens unit

(1) Remove the original glass and lens cover.


Take off the lens unit.

Note: 1. When installing the lens unit, fix it while it

is pushed in the direction of the white ar-

row.

2. Refer to “2.7.2 Lens unit” in the Service

Handbook to adjust the magnification ratio

of the lens.

3. When replacing the lens unit, do not touch

the screws shown with the arrows. [Rear side]

[Front side]

Connector Clamp

Exposure lamp

Lens unit

Connector


[F] Scanner motor

(1) Remove the rear side upper cover.

(2) Disconnect one connector.

(3) Detach the spring.

(4) Remove 2 screws and take off the scanner mo-

tor with the bracket attached.

Note: When installing the motor, take the following

procedure.

1. Fix the bracket to the frame temporarily.

2. Attach the tension spring to the bracket

and tighten the screws to fix the bracket

on the frame while the bracket and spring

are balanced.

[G] Carriages-1 and -2

(1) Remove 2 screws and take off the plate springs

of the front and rear sides.

Remove the ADF original glass.

ADF original glass Plate spring

Spring Connector

Scanner motor

4. Handle the unit with care. Do not touch

the adjusted area and lens. (Hold the unit

as the right figure.)Rear side

Front side

Lens

Adjustedarea


(5) Take off carriage-1 while inclining it.

(6) Take off mirror-1.

(7) Remove 2 screws and take off the inverter board.

Carriage-1

Inverter board

Mirror-1

(2) Move the carriages to the exit side.

(3) Remove 2 screws and take off the brackets fix-

ing the carrage-1 to the wire.

SLGboard

Lampcable

Sticker

(4) Remove the square sticker fixing the lamp cable

to the base and disconnect the connector of the

lamp cable from the SLG board.Connector


(12)Take off mirrors-2 and -3.

Mirror-2

Mirror-3

(9) Detach the tension springs of the front and rear

sides.

(10)Remove the carriage wires.

(11)Take off carriage-2 while its corner is pushed

into the window of the rail and inclining the car-

riage.

Tension spring Carriage wire

Window

Carriage-2

(8) Attach the wire holder jigs to the pulleys to pre-

vent the wires from loosening.

Note : Refer to “2.7.1 Adjustment of the carriages”

in the Service Handbook for the direction of

the wire holder jig when it is attached.

Wire holder jig

Pulley


[I] Home position sensor

(1) Disconnect one connector. Release the latches

and remove the home position sensor.

Home position sensor

[H] Platen sensor


and remove the platen sensor.Platen sensor

[J] Damp heater

(1) Remove the original glass, rear top cover and

lens cover.

(2) Remove one connector from the lens cover.

Remove 2 screws and take off the damp heater

for the lens.

Damp heater forthe lens

(3) Release the harnesses from 2 clasps and one

clamp and disconnect one connector.Connector

Lens cover

Clamp Clasp

Connector


(4) Move the carriages to the feed side. Remove 2

screws. Slide the damp heater for the mirrors to

the rear side and take it off.

Damp heater for the mirrors

December 2000 © TOSHIBA TEC 8 - 1 DP4500/3500 LASER OPTICAL UNIT

8. LASER OPTICAL UNIT

8.1 General DescriptionThe laser optical unit radiates the laser beam onto the photoconductive drum responding to the digital

image signals sent from the scanner, printer controller, etc. to create a latent image. The image signal is

converted into the light emission signal of the laser diode on the laser drive board, then radiated on the

drum through the optical elements such as the cylinder lenses, polygonal mirror and fØ lens.

The unit must not be disassembled in the field as it is very sensitive to dust and finely adjusted at the

factory.

DP4500/3500 LASER OPTICAL UNIT 8 - 2 December 2000 © TOSHIBA TEC

Front

Laser driveboard

Laser diode

Laser emission unit

Finite focus lens

Aperture

Cylinder lens

Polygonal mirror

Paper exit

Polygonal motor

fØ lens-1

Polygonal motordrive board

Rear

H-Sync detectionPC board

Slit glass(for outgoing laser beam)

H-Sync returning mirror

fØ lens-2

Front

Paper exit

Rear

[Appearance]

[Laser Optical Unit]


[CAUTION]

• Do not put the tools near the path of the laser beam.

• Take off your watch, rings, bracelets, etc. when handling the unit.

8.2 Structure(1) Laser emission unit

This unit consists of the laser diode, finite focus lens and aperture.

a. Laser diode

This laser diode features low droop, small laser variation and low threshold current.

The aperture determines the shape of the laser beam at the laser emission position.

The laser diode radiates the laser beams responding to the laser emission control (ON/OFF) signals

from the laser drive PC board. The laser beams which passed through the finite focus lens are

focused on the drum surface.

b. CAUTION

The beam of the semiconductive laser is very weak (about 5 mW), but the focused parallel rays

create great energy which is hazardous.

Some components of the laser optical unit are made of metal. However there is no danger of laser

leakage during the normal operation, since the unit is in a sealed container.

Note: The laser beam is not visible. Pay the closest attention when handling the laser unit components

or performing operations such as adjustment of the beam. This kind of operation which is very

dangerous must only be performed only by specially trained staff.

The warning label shown below is attached inside of the front cover.

DANGER–INVISIBLE LASER RADIATION WHEN OPTICAL UNIT OPEN OR DRUM UNIT REMOVEDAND INTERLOCK DEFEATED. AVOID DIRECT EXPOSURE TO BEAM.

VORSICHT–UNSICHTBARE LASERSTRAHLUNG, WENN DIE ABDECKUNG GEÖFFNET ODERDIE TROMMEL ENTFERNT UND DIE VERRIEGELUNG UNWIRKSAM GEMACHT WIRD.NICHT DIREKT DEM STRAHL AUSSETZEN.

DANGER –RAYON LASER INVISIBLE LORSQUE LE BLOC OPTIQUE EST OUVERT, LE

PELIGRO–RADIACION INVISIBLE DE LASER CUANDO LA UNIDAD OPTICA ESTA ABIERTA O LA UNIDAD

TAMBOUR RETIRE ET LE VERROUILLAGE HORS D'USAGE.EVITER L'EXPOSITION DIRECTE AU RAYON.

DEL CILINDRO ES RETIRADA Y CUANDO EL INTERRUPTOR DE SEGURIDAD ESTADESACTIVADO. EVITE EXPOSICION DIRECTA AL RAYO.

>PS<


(2) Polygonal mirror motor unit

This unit consists of the polygonal mirror, polygonal

mirror motor and polygonal mirror cover.

a. Polygonal mirror motor

This motor rotates the polygonal mirror at high

speed.

The DC motor controls the rotation speed of

the mirror motor as follows:

During standby : 10,000 rpm (approx.)

During copying : 38,000 rpm (approx.)

b. Polygonal mirror

The laser beams emitted from the laser diode

are reflected by this mirror. As the polygonal mir-

ror is rotated by the polygonal mirror motor, the

reflected laser light moves in sync with the

rotation. The direction of this movement is the

primary scanning direction of the image. One

scan is performed on one plane of the polygonal

mirror.

As the polygonal mirror has eight planes, eight

scans are performed in one rotation of the

polygonal mirror.

c. Polygonal mirror cover

The polygonal mirror cover reduces the windage

loss and noise, prevents adhesion of foreign

objects on the mirror surface and releases heat.

One scan is completed by completion of steps (A)through (C). One scan is performed on one plane of thepolygonal mirror. Eight scans can be made with onerotation of the polygonal mirror.

Laser light

Drum

Laser light

Drum

Laser light

Drum

Fig. 8.2-1

(B)

(A)

(C)


(3) fØ lenses -1 and -2

These two lenses perform the following corrections on the laser beams reflected by the polygonal mirror.

a. Uniform-velocity scanning

Since the polygonal mirror is rotating at a uni-

form velocity, the laser beam reflected from the

mirror scans over the drum surface at the same

angle; namely, the pitch between the dots on

the drum is wider at both ends than at the center

of the scanning range. The fØ lenses correct this

difference, making all the dot-to-dot pitches

equal on the drum surface.

b. Face tilt correction

The reflecting face of the polygonal mirror is

tilted slightly to one side against the perfect

vertical. The fØ lenses correct the displacement

of the laser beam on the drum (against the

horizontal direction) which occurs due to the tilt

of the reflecting face.

c. Sectional shape of laser beam

The shape of the laser beam spotted on the

drum is adjusted.

Wider

Narrower

Drum

Lens-1Lens-2

Same intervals

Mirror plane is tilted. Deviation

(4) H-Sync detection PC board

The laser light started to be scanned by one of the reflected faces of the polygonal mirror is reflected

by the H-Sync detection mirror and goes into the PIN diode on the H-Sync detection PC board. The

primary scanning synchronizing signal is generated based on this incomming laser light.

Fig. 8.2-2

Fig. 8.2-3


(5) Laser Drive Board

This control board has the following functions:

a. APC control function (corrects disparity of the laser intensity caused by temperature)

b. Laser ON/OFF function

c. Function to generate the primary scanning synchronizing signals

(6) Slit glass

The slit glass is located where the laser beams are output from the laser optical unit, and it protects the unit

from dust.


Fig. 8.3-2 shows a block diagram of the semiconductive laser control circuit. The semiconductive laser

performs monitor efficiency regulation (a process to control the monitor current for the light amount), and

laser itself is adjusted to output initially an emission of approx. 2.11mW (421 µW on the drum surface). The

regulated voltage of the monitor output is fed back to the laser power comparison circuit. This monitor

output voltage is compared with the laser power voltage set for the control circuit for every scanning. The

laser driver circuit increases the forward current if the laser power is insufficent and drecreases the current

when the power is excessive to maintain a constant optical output.

8.3 Laser DiodeThe laser used in this copier is a AlGaAs type semiconductive laser. It is oscillated in the single-horizontal

mode and its wavelength is approx. 785 nm. This semiconductive laser outputs 5mW with a standard DC

power supply. Laser intensity is controlled using the output from the PIN diode for light output monitoring in

the semiconductive laser.

The relation between the current and optical out-

put of the semiconductive laser is as shown on the

right. Light emission is started when the forward cur-

rent reaches or becomes greater than the threshold

current, and outputs the monitor current which is

proportioned to the optical output. The threshold

current and monitor current vary depending on each

semiconductive laser due to their individual

characteristic. The optical output has to be adjusted

to maintain a constant value.

Since the optical output of the semiconductive la-

ser is decreased when the temperature of the la-

ser rises, the APC control needs to be performed to

maintain a constant optical output.

Fig. 8.3-2 Block diagram

Threshold currentO

ptic

al O

utpu

t (m

W)

Low temp.

High temp.

Forward current

Monitor current

Current (mA)

Monitor outputMonitor effi-ciency regula-tion circuit

Laser powercomparisoncircuit

Laser drivercircuit

Semiconductive laser

Constantoptical output

Fig. 8.3-1

Regulation

Power source


Plate cover

Laser unit fan

(3) Remove 4 screws and take off the plate cover

of the system unit.


Take off the laser unit fan.

[B] Laser optical unit

(1) Remove 2 screws and take off the bracket.

(2) Remove 4 fixing screws at the front side and 3

at the rear side of the system unit.

[Front side]

[Rear side]

8.4 Disassembly and Replacement[A] Laser unit fan

(1) Take off the rear side upper/lower covers, re-

ceiving tray, exit side rear cover (with the option

cover attached) and left cover.

(2) Remove 7 screws and take off the stay.

Stay

Bracket

(3) (3)

(4)

[B] (1)

(3)

(4)[B] (1)

(3)


(3) Disconnect all connectors of the logic PC board

and 2 of the system PC board.

(4) Release all harnesses from the clamps.

Logic PC board

System PCboard

Connectors of system PC board

(5) Remove one binding band at the rear side.

(6) Pull out the system unit in the direction of the

arrow.

Binding band

System unit


(7) Remove the 3 fixing screws of the laser optical

unit.

(8) Take out the laser optical unit.

Notes: 1. The laser optical unit should be placed with

the motor facing upwards and not

impressing any load on it.

2. Do not leave fingerprints or stains on the

slit glass.

3. The laser optical unit is a precise

apparatus.

Pay close attention not to make any impact

or vibration on it.

4. The laser optical unit is precisely adjusted

and very sensitive to dust and stains. Do

not disassemble the unit in the field.

[Fixing screws of laser optical unit]

December 2000 © TOSHIBA TEC 9 - 1 DP4500/3500 PAPER FEEDING SYSTEM

9 PAPER FEEDING SYSTEM

9.1 FunctionsThe purpose of this system is to pick up paper from the cassette or bypass tray and send it to the transfer

section.

The paper feeding system mainly consists of the pickup roller, feed roller, separation roller, transport roller,

registration roller, bypass paper sensor, paper-empty sensor, paper-stock senser, feed sensor, registration

sensor and the drive system for these components.

(1) Pickup roller

This roller moves up and down to draw out a sheet of paper from the bypass tray or the cassette and

send it to the feed roller.

(2) Feed roller

This roller is mounted against the separation roller. It transports the paper from the pickup roller to the

registration roller.

(3) Separation roller

This roller is mounted against the feed roller. When two sheets of paper or more are sent from the

pickup roller, the load of the torque limiter of the separation roller is greater than the frictional force

between the sheets. As the result, the separation roller is stopped and the lower sheet of paper is not

advanced any further. When only one sheet of paper is sent from the pickup roller, the separation roller

is forced to rotate following the feed roller.

(4) Separation pad

This pad is mounted against the bypass feed roller. When two sheets of paper or more are sent from

the bypass pickup roller, the friction between the separation pad and the paper is greater than that

between the sheets. Therefore, the sheet(s) other than the paper at the top is(are) not transported any

further. When only one sheet is sent from the bypass pickup roller, the paper is transported forward due

to the friction between it and the bypass feed roller.

(5) Transport roller

This roller transports the paper sent from the feed roller to the registration rollers.

(6) Registration roller

Paper sent from the feed roller is pushed against the registration rollers, which align its leading edge.

The registration rollers then rotate to transport the paper to the transfer section.

DP4500/3500 PAPER FEEDING SYSTEM 9 - 2 December 2000 © TOSHIBA TEC

The following is the sensors which detect the presence/absence of paper and the position of the paper

being transported, to control the ON/OFF of the rollers.

(7) Bypass paper sensor

This sensor detects if paper is set in the bypass tray. If it is, bypass feeding is performed in preference

to cassette feeding.

(8) Paper-empty sensor

This is a emission type sensor and detects the presence/absence of paper in the cassette using an

actuator. When there is no paper in the cassette, the actuator blocks the light path of the sensor, and

the sensor determines that there is no paper.

(9) Paper-stock sensor

This is a emission type sensor which detects the amount of paper remaining in the cassette using an

actuator. When the remaining paper is almost finished and has become around 100 sheets, the actua-

tor blocks the light path of the sensor to notify that the paper quantity is getting less.

(10) Feed sensor

This sensor detects if the leading edge or trailing edge of the paper passed the feed roller. It also

detects jams such as paper misfeeding.

(11) Registration sensor

This sensor detects that the leading edge of the paper has reached the registration roller and the trailing

edge of the paper has passed the registration roller.


Sectional view of paper feeding section (Front side)

No. Name

1 Bypass separation pad

2 Bypass feed roller

3 Bypass pickup roller

4 Upper cassette separation roller

5 Upper cassette feed roller

6 Upper cassette pickup roller

7 Transport roller

8 Lower cassette separation roller

No. Name

9 Lower cassette feed roller

10 Lower cassette pickup roller

11 Bypass paper sensor

12 Registration sensor

13 Registration roller (rubber roller)

14 Registration roller (metal roller)

15 Upper feed sensor

16 Lower feed sensor

2 311

13

4

14

1

6

7

8

10

12

15

5

9

16


Paper feeding section drive system (Rear side)

No. Name

17 Bypass feed clutch

18 Transport clutch (low speed)

19 Transport feed clutch (high speed)

20 Upper cassette feed clutch

21 Lower cassette feed clutch

(G20/G25)(Clutch/G28)

(Clutch/G28)

(Clutch/G28)

(Clutch/G28)

(Clutch/G35)

17

18

19

21

20

(G27/G18)

(G24/G30)

(G40/G34)

(G31/G38)

(G35)

(G34)

(G35)

(G33)

(G33)

(G27/G21)

(G23)(G21)


9.2 Description of Operations9.2.1 Operation of bypass pickup roller

When driving force is applied to the feed roller, the rotational force is transmitted to the pickup lever via the

spring clutch, and the pickup arm falls by its own weight. At this time, the pickup lever is stopped when the

spring clutch contacts with the stopper.

When the driving force is removed from the feed roller, the pickup lever and pickup arm are lifted up by the

force of the lever spring.

9.2.2 Operation of cassette pickup roller

When the cassette is inserted, the protrusion at the rear side of the cassette turns the lever (a) up in the

direction of the arrow A. The pickup roller and roller holder are then lowered by the spring (b).

Spring clutch

Feed roller

Lever spring

Pickup arm

Pickup roller

Pickup lever

Insertion direction

Lever (a)

Pickup roller

Spring (b)

Roller holderA


9.2.3 Separation of paper

This model is equipped with a separation roller which

works to prevent multiple paper feeding. The sepa-

ration roller unit consists of the feed roller, separa-

tion roller, spring joint, etc., as shown in the right

figure.

The feed roller is rotated by the feed clutch in the

direction of the arrow ( ) at the same timing as

the pickup roller rotation.

The figure at lower right shows how duplicate feed-

ing is prevented: Since the friction between two

sheets is small, the lower sheet is stopped by the

separation roller and is not transported any further

while the upper sheet is transported by the feed roller

in the direction of the arrow ( ).

[Example]

When only one sheet enters between the rollers:

Since the transporting force of the feed roller is

greater than the braking force of the separation roller,

the separation roller is forced to rotate following the

feed roller, making the sheet go forward to the regis-

tration roller.

When two sheets enter between the rollers at the

same time:

Since the transporting force of the feed roller and

the breaking force of the separation roller are greater

than the frictional force between two sheets, the pa-

per A is transported in the direction of the arrow

( ) and the paper B is braked by the separation

roller and is not transported any further.

Feed roller

Separation roller

Spring joint

Feed roller

Separation roller

A

B


9.2.4 General operation

[A] From power ON to standby status

(1) When the copier is turned ON, the tray-up motor starts to rotate forward and the upper cassette tray

starts to rise. When the tray-up sensor is turned ON (L n H), the tray-up motor is turned OFF causing

the tray to stop. At this time, if the empty sensor is OFF (L), it is judged that there is no paper in the

cassette. If the empty sensor is ON (H), there is paper in the cassette. The tray stops at raised position

regardless of the presence/absence of paper. The tray-up motor then starts to rotate in reverse and the

lower cassette tray starts to rise. The lower cassette tray is stopped in the same manner as the upper

cassette tray, and the empty sensor detects if there is paper in the cassette.

(2) If the cassette is not completely inserted when the copier is turned ON, the tray in that cassette does

not rise. When the cassette is inserted completely, the tray is raised and checks the presence/absence

of paper.

(3) If either of the feed sensors is ON (meaning there is paper on the transport path) when the copier is

turned ON, it is determined that a paper jam has occurred and no operation is enabled until the jammed

paper is removed.

[B] Standby status

(1) After the tray is moved up to check the presence/absence of paper as described above, the copier

enters the standby state. In the standby mode, the tray remains at the raised position.

(2) When a cassette is inserted or removed in the standby state, the tray is raised again and checks the

presence/absence of paper.

[C] Bypass feeding

• The bypass paper sensor detects paper in the bypass tray.

• The bypass feed clutch is turned ON, and then the bypass pickup roller and bypass feed roller are

rotated.

• The bypass pickup roller is lowered to start feeding the paper.

• The leading edge of the paper turns the registration sensor ON and the paper is aligned by the

registration rollers.

• The bypass feed clutch is turned OFF, causing the bypass pickup roller and bypass feed roller to

stop rotating. The bypass pickup roller moves up.

• The registration clutch is turned ON, and the paper is transported to the transfer section.


[D] Cassette feeding

(D-1) Lower cassette

• The feed clutch and transport clutch (high speed) are turned ON, and the pickup roller, feed roller

and the transport roller are rotated to start feeding paper.

• The leading edge of paper turns ON the lower feed sensor. The feed clutch and transport clutch

(high speed) are then turned OFF and back ON.

• The leading edge of the paper turns ON the registration sensor and the paper is aligned by the

registration rollers.

• The feed clutch and transport clutch (high speed) are turned OFF causing the pickup roller, feed

roller and transport roller to stop rotating.

• The registration clutch and transport clutch (low speed) are turned ON, and the paper is trans-

ported to the transfer section.

(D-2) Upper cassette

• The feed clutch is turned ON and the pickup roller and feed roller start to rotate to start feeding the

paper.

• The leading edge of paper turns ON the registration sensor, and the paper is aligned by the regis-

tration rollers.

• The feed clutch is turned OFF causing the pickup roller and feed roller to stop rotating.

• The registration clutch is turned ON, and the paper is transported to the transfer section.


1 2 3 4 5 6 7

IN1 IN2 M(+) GND M(–) N.C. VCC

9.3 Drive Circuit of Tray-up MotorTray-up motor (T-UP-MTR) : Driven by IC44 (upper/lower cassettes) (LGC: TA8428)

Block diagram of TA8428

IN1 and IN2 are input terminals to receive the signals from the microcomputer. The control logic, based on

the signals from the microcomputer, controls the rotation direction and ON/OFF of the motor.

Input Output

IN1 IN2 M (+) M (–)Remarks

H H L L BRAKE

L H L H CCW (upward)

H L H L CW (downward)

L L OFF (high impedance) STOP

Control logic

Thermal shut-down over-current protec-tion circuit

(Not used)


9.4 Disassembly and Replacement[A] Bypass feed unit

(A-1) Bypass feed unit

(1) Remove the feed side rear hinge cover.

(2) Disconnect one connector and release the har-

ness from the clamp.

(3) Remove 2 screws. Release 2 hooks while the

bypass feed unit is lifted up, then take it off to-

ward you.

(A-2) Paper size detection board

(1) Release the harnesses from 3 clamps and dis-

connect one connector.

(2) Remove 2 screws and take off the hinge unit.

(3) Detach the bypass tray from the protrusion at

the fulcrum of the frame.

Clamp

Fulcrum

Bypass tray

Hinge unit

Connector

Clamp

Connector


(4) Remove 3 screws and release 4 latches.

Take off the bypass tray upper cover.

(5) Remove one screw and plate spring.

(6) Remove one screw (indicated with a white ar-

row) from the back, then take off the bracket.


screw. Take off the paper size detection board.

Note: When reassembling the bracket, make sure

that the pointer of the bracket is positioned

as it was before the disassembly.

Bypass tray upper cover

Latch

Latch

Bracket

Plate spring

Connector

Paper size detection board

Pointer


(A-3) Separation pad


(2) Pull the separation pad in the direction of the

arrow to remove it from the bracket.

Detach the spring and then take off the pad.

(A-4) Bypass feed roller

(1) Remove one screw and take off the front side

paper guide.

(2) Remove one clip and take off the bypass feed

roller together with the one-way clutch.

(A-5) Bypass pickup roller

(1) Remove 2 screws and take off the bypass feed

cover.

Bracket

Separation pad

Spring

Bypass feed cover

Bypass feed roller

One-way clutch

Clip

Front side paper guide

(A-5)

(A-5)

(A-4)

(2) Remove one clip and pull out the shaft in the

direction of the arrow. Detach the timing belt,

and take off the bypass pickup roller.

Shaft

Clip

Timing belt

Bypass pickup roller


Notes: Pay attention to the following when assem-

bling the bypass feed roller and pickup roller.

1. Put the timing belt securely around the

pulley.

Make sure that the belt is also put on the

belt tensioner.

2. Put the timing belt on the bypass pickup

roller correctly.

3. Attach the clip in the groove on the shaft

securely.

4. Make sure that there is no dirt or oil stain-

ing on the surface of the timing belt, pul-

ley and rollers.

5. Pay attention to the direction of the by-

pass pickup roller and feed roller when

they are installed.

(A-6) Bypass paper sensor

(1) Release the harness from the 2 clamps. Re-

move one screw and take off the sensor bracket.

(2) Disconnect the connector. Release the latches

and take off the bypass paper sensor.

Feedingdirection

Pickup roller

Feed roller

Separation pad

ConnectorBypass paper sensorClamp


(A-7) Bypass feed clutch

(1) Release the harness from the 2 clamps and dis-

connect the connector. Remove the E-ring.

(2) Remove 4 screws. Take off the bypass feed roller

unit sliding it in the direction of the arrow.

(3) Remove one E-ring and loosen one setscrew.

Take off the bypass feed clutch.

Note: When assembling the bypass feed clutch,

push it against one end (feed roller unit side)

of the groove on the shaft.

Setscrew Feed clutch

ConnectorClamp

E-ring

Bypass feed roller unit

Groove

E-ring


[B] Lower feed sensor

(1) Remove the feed side lower cover.

(2) Open the jam access cover, and take out the

transfer/separation charger. ( Chapter 11.5)

(3) Disconnect 3 connectors.

(4) Disconnect the fan connector of the front side

while the jam access cover unit is lifted up and

moved slightly in the direction of the arrow, then

take off the jam access cover unit.

(5) Remove one screw and take off the terminal

cover, then disconnect the connector.

(6) Remove 3 screws. Slide the transport guide unit

to the rear side and take it off from the front

side.

Transport guide unit

Terminal cover

Connector

Fan connector

Connector

Note: Make sure that the harnesses are securely

caught under the hooks when the connec-

tors of the transfer/separation charger are

connected.

Hook Black

Red

Red(in a black tube)


[C] Registration sensor and upper feed sensor

(1) Remove the front side right cover.

(2) Release the latch from the shaft, and take off

the jam release knob.

(3) Disconnect one connector, remove one clamp

and 2 screws. Take out the pre-registration guide

from the front side.

(4) Remove one screw and take off the registration

sensor with the bracket attached.


and remove the registration sensor.


and remove the upper feed sensor.

Note: Do not damage or deform the roller rests

when installing/removing the pre-registration

guide.

Front side right cover Jam release knob

ConnectorPre-registration guide

Bracket

Registrationsensor

Upper feed sensor


and remove the lower feed sensor.

Connector

Lower feed sensor

Clamp

Roller rest

Roller rest


[D] Registration roller

(1) Disconnect one connector and loosen one set-

screw.

Remove the rear side registration clutch.

( Chapter 10.4)

(2) Remove the cleaner unit. ( Chapter 11.5)

(3) Remove the E-rings from the front and rear sides

(one each). Slide the registration roller (rubber

roller) to the rear side and take it off from the

front side.

(4) Remove the E-rings and detach the springs from

the front and rear sides (one each). Take off the

registration roller (metal roller).

[E] Tray drive unit


tor. Take off the tray drive unit with the metal

sheet attached.

(2) Remove 4 screws and take the tray drive unit

apart from the metal sheet.

(3) Turn the tray drive unit. Release 6 latches and

remove the cover.

Note: When removing the cover, be careful of the

spring inside the tray drive unit pushing the

cover.

[Front side]

[Rear side](3) E-ring

Connector

Latch

Latch

Registration roller

(4) Spring

(4) E-ring

(4) Spring

(4) E-ring

(3) E-ring

Cover

(1) (1)

(1)

(2)

(1)

(2)(1)

(2)

(2)

(1)


(4) Remove the tray-up motor.

Note: When assembling the tray drive unit, match

the gear bosses with the holes of the cover.

[F] Transport clutch

(1) Remove one E-ring and 3 screws.

Take off the metal cover of the transport clutch.

Note: Do not move the transport roller shaft when

attaching the metal sheet cover. Fix the

screws in the order of (a), (b)and (c). Open

the side cover and check if the transport roller

rotates smoothly after it was attached.

(2) Remove the gears, disconnect the connectors

and loosen the setscrews.

Remove the transport clutches.

Notes: 1. Remember that the upper and lower

clutches are different in the diameter of

their shafts.

Upper clutch: 8mm

Lower clutch: 6mm

2. Attach the clutches to the shafts refer-

ring to the figure on the lower right.

[G] Cassette detection switch

(1) Pull out the cassette.


and remove the cassette detection switch from

the front side.

Gear Connector

Boss

Tray-up motor

Cassettedetectionswitch

E-ring

Clutch

Shaft0~0.5mm

(c)

(b)

(a)

Transport roller shaft

Metal sheetcover


[H] Cassette feeding unit

(H-1) Cassette feeding unit

(1) Remove the cassette.

(2) Remove one screw and take off the cassette

feeding unit sliding it to the front side.

Cassette feeding unit

(H-2) Tray-up sensor


and remove the tray-up sensor.

(H-3) Paper-empty


and remove the paper-empty sensor.

(H-4) Paper-stock sensor


and remove the paper-stock sensor.

(H-5) Separation roller

(1) Remove one screw and take out the separation

roller holder.

(2) Remove the lever from the holder.

Take off the separation roller together with the

shaft.

(3) Remove the cover, arbor and clutch spring from

the shaft. Take off the separation roller.

Separation roller Feed clutch

Paper-empty sensorTray-up sensorPickup roller

Feed rollerPaper-stocksensor

[Separation roller]

Holder

Cover

Clutch spring

Separation roller

Shaft

Arbor

Spring

Lever

Arbor

Spring

(H-6) Feed roller

(1) Remove the clip and take off the feed roller.

Notes: 1. The feed roller and pickup roller are the same component parts.

2. There is a spring clutch inside the feed roller. Remove the feed roller together with the gear.

(H-7) Pickup roller

(1) Remove the clip and take off the pickup roller.

Note: There is a spring clutch inside the pickup roller. Remove the pickup roller together with the gear.


(H-8) Feed clutch

(1) Disconnect one connector, detach one spring,

remove 2 screws and loosen one setscrew. Take

off the feed clutch.

Connector

Setscrew

Spring

December 2000 © TOSHIBA TEC 10 - 1 DP4500/3500 DRIVE SYSTEM

10. DRIVE SYSTEM

10.1 General DescriptionThe drive system drives the drum, developer unit, cleaner unit, fuser unit, transport roller, cassette feed

roller and registration roller.

The drive system is driven by the rotation of the main motor.

10.2 Functions• Drum drive ............................. Drives the drum by transmitting the rotation of the main motor through the

gears to the drum flange gear.

• Developer unit drive ............... Drives the developer unit by transmitting the rotation of the main motor

through the gears to the developer unit gears.

• Fuser unit drive ...................... Drives the fuser unit by transmitting the rotation of the main motor through

the gears to the fuser unit gears.

• Cleaner unit drive ................... Drives the cleaner unit gear by the rotation of the drum flange gear.

• Registration roller drive .......... Drives the registration rollers by transmitting the rotation of the main motor

through the gears and clutches.

• Transport roller drive .............. Drives the transport roller by transmitting the rotation of the main motor

through the gears and clutches.

• Cassette feed roller drive ....... Drives the cassette feed roller by transmitting the rotation of the main

motor through the gears and clutches.

Main motor

Developerunit drive gear

(G36/G21)

Feeding systemdrive gear

Cleaner unitdrive gear

(G22)

Registration rollerdrive unit

(G50/G27)

(G72/G30)

(G25/G14)

(G27)

(G23)

(G24)(G23)

(G47)

(G25)

(G33)

(G24)

Fuser unitdrive gear

(G64/G30)(G28/G25)

(G10)

DP4500/3500 DRIVE SYSTEM 10 - 2 December 2000 © TOSHIBA TEC

+(MAMCK)

MAMPL

MAMCW

MAMBK

MAMON

10.3 Main Motor10.3.1 Main motor drive

Difference

Speedcomparator

Rotationcontrol

Voltagedetectioncircuit

Excitationphaseswitchingsection

Rotorpositiondetection

Phasecomparator

Hall element A

FG pulse

Phase W

Phase V

Phase U

Main motor

Controlsignal

(1) LGC outputs the control signals for the the main motor rotation. (MAMCW: Motor rotation direction

setting, MAMON: Motor rotation command)

(2) The excitation phase switching section excites each phase of the main motor nnnnn The main motor is

rotated.

(3) Hall elements A, B and C detect the rotation position of the motor (rotor).

(4) The excitation phase switching section switches the excitation of each phase.

(By repeating (2) through (4), the motor keeps rotating.)

(5) An FG pulse is generated by the FG pattern of the encoder attached to the main motor.

(6) The FG pulse and the reference frequency from the LGC are compared in terms of the phase and

speed, and the difference is added to the IC1. The fluctuations in the power supply voltage is also

added to the value. (Signal generation)

(7) In accordance with the signal obtained in the step (6), the excitation phase switching section changes

the switching timing.

i.e. The FG pulse and reference frequency are controlled to be equal. nnnnn The main motor rotates at a

fixed speed. (Locked range)

(8) When the main motor enters the locked range, the excitation phase switching section outputs the

MAMPL signal to the LGC. (“L” level)

(9) When the MAMBK from the LGC becomes “L” level, the main motor is braked. When the MAMON signal

becomes “H” level, the main motor is stopped.

Hall element C

Wavecorrection

Photo-interruptor

Hallelement B

Reference frequency

Lockprotectioncircuit

Difference


10.3.2 Control signals

(1) MAMCW signal (LGC nnnnn MTR: Input)

This is a signal to switch the direction of the main motor rotation. When this signal becomes “L” level,

the main motor rotates counterclockwise as seen from the rear side, and drives the developer unit,

drum, fuser roller, etc to the appropriate direction.

(2) MAMPL signal (MTR nnnnn LGC: Output)

When the difference of the FG pulse cycle against the reference frequency is within ±6.25%, it is

specified that the motor is in a lock range (normal rotation), and this MAMPL signal becomes “L” level.

At this time, the LED “D4” is lit.

(3) MAMCK signal (LGC nnnnn MTR: Input)

This is a reference clock signal to rotate the main motor at a fixed speed.

(4) MAMBK signal (LGC nnnnn MTR: Input)

This is a signal to stop the main motor.

When it becomes “L” level, the main motor is braked.

(5) MAMON signal (LGC nnnnn MTR: Input)

This is a signal to turn ON/OFF the main motor. When it becomes “L” level, the motor is rotated.

Signal level of the motor circuit

Signal Level “H” Level “L”

MAMCW CCW direction CW direction

MAMPL Abnormal rotation Normal rotation

MAMCK Reference clock

MAMBK Brake OFF Brake ON

MAMON Motor OFF Motor ON

* The signal names are for the connector J313(LGC).


(3) Turn over the gear unit and remove 2 screws to

unfix 2 terminals.

Note: Do not bend the plate spring attached to the

terminal when installing or removing the gear

unit.

(4) Remove one screw and disconnect one connec-

tor. Take off the toner bag full detection sensor

with the bracket attached.

(5) Remove the E-rings and take off the gears.

Note: When assembling the gear unit, set the gears

referring to the figure in the page 10-1, and

pay attention to the position of each gear.

10.4 Disassembly and Repalacement[A] Main motor

(1) Take off the rear side upper/lower covers.

(2) Take off the developer unit cooling fan unit

( Chapter 11.5)

(3) Disconnect one connector, remove 2 screws and

release one lock support. Take off the main mo-

tor with the board attached.

[B] Registration clutch

(1) Disconnect one connector and remove one set-

screw. Take off the registration clutch.

[C] Gear unit

(1) Remove 5 screws and disconnect 3 connectors.

(2) Take off the gear unit while the arm is held up.

ConnectorRegistration clutch

Main motor

Set-screw

Connector

Connector Arm

Locksupport

Plate spring

Connectors

Toner bag fulldetectionsensor

(3)(3)

(4)


[D] Drum drive gear

Note: Do not loosen or remove the 3 red screws

fixing the bracket of the drum drive gear.

Bracket

Drum drive gear

December 2000 © TOSHIBA TEC 11 - 1 DP4500/3500 DRUM AREA

11. DRUM AREA

11.1 ConfigurationThe parts and units located around the drum and the drum itself are described in this section.

This area mainly consists of the following.

• Cleaner unit Drum

Main charger

Cleaner Cleaning blade

Toner recovery blade

Toner recovery auger

• Transfer / separation charger

• Sub-separation fan / Exhaust fan

• Discharge lamp

• Toner bag / Toner bag full detection sensor

• Developer unit cooling fan / Middle cooling fan

• Drum thermistor

[Sectional view of drum area]

Discharge lamp

Middle cooling fan

Toner recovery auger

Drum

Cleaning bladeSub-separationfan

Exhaust fan

Separationcharger

Toner recovery blade

Transfer charger

Transfer guide

Main charger

Drum thermistor

DP4500/3500 DRUM AREA 11 - 2 December 2000 © TOSHIBA TEC

11.2 Functions(1) Drum

The drum is made of a cylindrical aluminum base coated with thin film of organic photoconductive

substance.

The photoconductive object becomes insulative (the electrical resistance is high) when it is not ex-

posed to the light and electrically conductive (the electrical resistance is low) when it is exposed to the

light. This object is called a photoconductor.

(2) Main charger

The main charger consists of a metal rod with U-shaped section, insulated blocks at both ends of the

rod and charger wire attached between them.

When a high voltage is applied to the charger wire, the air around it is charged (ionized). The ionized air

then flows into the drum causing it to be charged. This phenomenon is called “corona discharge”.

Negative charge caused by the corona discharge is applied to the drum surface evenly in dark place.

The main charger is equipped with a wire cleaner to clean the wire.

(3) Cleaner

(a) Cleaning blade

This blade is pressed against the drum surface with a constant force by the pressure springs, and

scrapes off the residual toner from the drum surface.

(b) Recovery blade

This blade catches the toner scraped off by the cleaning blade.

(c) Toner recovery auger

This auger carries the residual toner scraped off to the toner bag.

(4) Transfer/separation charger

(a) Transfer guide

This guide guides the paper transported from the feeding unit to the transfer section.

Positive (+) bias voltage is applied to the guide to prevent the transferability being lowered under

conditions such as high humidity.

(b) Transfer charger

The transfer charger applies a charge (= positive charge) which is contrary to the charging polarity

of the toner to the back of the paper. The toner image is transferred electrostatically on paper by

performing this corona discharge.


(c) Separation charger

After the transfer process, the corona discharge applies a bipolar charge (AC) on the back of the

paper to separate the paper adhering to the drum surface.

(5) Sub-separation fan

This fan works to help the separation of paper from the drum surface by sucking the air from the back

of the paper.

(6) Discharge lamp

Discharging is a process to decrease or eliminate the static electricity on the drum surface.

The electrical resistance of the photosensitive layer is decreased by the light irradiation, and the

residual charge on the drum surface is neutralized and eliminated (cleaned). The electrical potential of

the drum surface is fixed to a certain amount before the drum is charged (The pre-exposure effect).

(7) Toner bag

The residual toner scraped off the drum surface by the cleaning blade is disposed in this bag.

(8) Toner bag full detection sensor

When the toner bag is full of used toner, the toner recovery auger in the cleaner is pushed back by the

toner and blocks the light emission of this sensor, as the result, notifying that the toner bag is full.


PWA-F-LGC-320 PS-HVT-320

IC2

IC13 IC10IC31

BC-RAM Vc

11.3 Output Control Circuits of High-Voltage Transformer11.3.1 Overview

• Generate the output control voltage Vc of the main charger, transfer/separation charger, transfer guide

bias and developer bias.

• Convert Vc n n n n n The current is output linearly.

11.3.2 Description of operations

• Outputs the adjustment value of the main, transfer and separation chargers and developer bias in the

BC-RAM to the main CPU.

x

• Outputs the control voltage data from the main CPU to the D/A converter.

x

• Converts to the analog data by the D/A converter.

x

• Outputs the control voltage Vc to the main, transfer and separation chargers, transfer guide bias and

developer bias transformer.

x

• The main, transfer and separation chargers, transfer guide bias and developer bias transformer generate

output current or voltage which is proportional to the control voltage Vc.

* Adjustment of the control voltage Vc (change of adjustment data) is performed in the adjustment mode.

* The output value of the transfer guide bias is fixed when the high-voltage transformer is shipped from

the factory.

MainCPU

D/Aconverter Output

AnalogDigitaldata

Main/transfer/separation/chargers,developerbias andtransferguide bias

Gatearray

Adjustmentvalue


J311-14 HVSAV

J311-17 HVTVR

J311-19 HVDVR

J311-21 HVMVR

MAINCPU

BC-RAM

IC13

IC10IC31

IC2

Gatearray

D/Aconverter

Separation charger

Developer bias

Transfer charger

Main charger


11.4 Drum Temperature Detection Circuit(1) Purpose of the drum temperature detection circuit

The amount of charge on the drum surface varies greatly with the surface temperature of the drum. This

circuit detects the temperature of the drum surface, and the amount of charge on the drum surface is

controlled to be constant based on the result.

(2) Configuration of the drum temperature detection circuit

Drum temperature detection circuit

The voltage developed through R38, thermistor and R37 is input via an analog multiplexer (IC94) to the

microcomputer as a temperature signal.

TH

C47

GND GND

+5V

100

R158 DRMTH-1CPU

R37

R380


11.5 Disassembly and Replacement[A] Cleaner unit

(1) Open the front cover and take out the toner bag

and developer unit. ( Chapter 12.5)

(2) Open the bypass feed unit, ADU and jam ac-

cess cover.

(3) Remove 2 screws and pull out the cleaner unit.

[B] Main charger

(B-1) Main charger

(1) Pull out the cleaner unit.

(2) Release the latches and pull out the main charger

in the direction of the arrow.

Note: Do not touch or damage the drum surface.

(B-2) Main charger grid

(1) Push the terminal head at the front side to

remove the grid.

Note: Do not touch the mesh pattern of the grid.

(B-3) Charger wire

* Length: 363mm, tungsten wire; diameter 0.06mm

(1) Remove the terminal covers of the front and rear

sides.

Cleaner unit Jam access cover

Developer unit

Latch

Grid

Push

Terminal cover

[Rear side] [Front side]


(2) Remove the terminal, detach the spring and take

off the wire.

Notes: Be careful of the following when attaching

the wire.

1. Put the wire in the V-grooves of the front

and rear sides.

2. Do not twist the wire.

3. Do not touch the wire directly with your

bare hands.

(B-4) Wire cleaner

(1) Release the lock at the front side of the wire

cleaner.

(2) Turn the wire cleaner in the direction of the ar-

row, and pull out the cleaning pad unit from the

charger case window.

(3) Remove the cleaning pads.

Note: When attaching the wire cleaner, send the wire

cleaner to the rear side end and be sure that

the 2 cleaning pads do not touch the wire.

[Rear side] [Front side]

V-groove

Spring Terminal

Lock Charger case window

Cleaning padWire cleaner

Cleaning pad

[C] Drum

(1) Pull out the cleaner unit and remove the main

charger.

(2) Release the latch and take off the cleaner stay.

Cleaner stay

Latch


[D] Cleaner

(D-1) Cleaning blade

(1) Pull out the cleaner unit. Remove the main

charger and the drum.


Note: Do not touch or damage the edge of the clean-

ing blade.

(D-2) Recovery blade

(1) Remove the recovery blade.

Notes: 1. When attaching the recovery blade, clean

the frame of the cleaner side and make

sure not to deform the blade.

2. Attach the recovery blade while it is

pushed against the part with a difference

in level on the surface of the frame.

3. Press the part sticking to the cleaner with

the double-sided adhesive tape to attach

the blade securely.

Cleaning blade

Recovery blade

(3) Turn the lever to the left to release the lock. Pull

out the drum shaft.

(4) Take off the drum upward.

Drum gear

Lever

Notes: 1. Release the pressure of the cleaning blade

using a jig before installing the drum.

2. Insert the jig into space made by pressing

the blade holder as shown in the right

figure.

3. Do not touch or damage the edge of the

cleaning blade.

Space to insert the jig


(D-3) Separation finger

(1) Remove 3 separation fingers.

Notes: 1. Remove the drum before replacing the

separation fingers to prevent damaging

the drum surface.

2. After the separation fingers are replaced,

check if the pressurization of them is nor-

mal using your finger.

Separation finger

(E-2) Charger wires

* Length: 353mm

2 tungsten wires: diameter 0.06mm

(The transfer charger wire and separation charger

wire are the same component parts.)

(1) Remove the separation supporter.

(2) Remove the terminal covers of the front and rear

sides.

(3) Remove the terminals, detach the springs and

take off the wires.

Notes: Be careful of the following when attaching

the charger wires.

1. Put the wires in the V-grooves of the front

and rear sides.

2. Do not twist the wires.

3. Do not touch the wires directly with your

bare hands.

Terminal cover

Separation supporter

[Rear side][Front side]Spring

TerminalV-groove V-groove

[E] Transfer/separation charger

(E-1) Transfer/separation charger

(1) Open the bypass feed unit, ADU and jam ac-

cess cover.

(2) Release the latches and remove the transfer/

separation charger.

Note: Do not deform the plate spring when the

charger is attached.

Latch

Platespring


[F] Exhaust fan and sub-separation fan

(1) Open the jam access cover.

(2) Take off the transfer/separation charger.

(3) Remove 2 screws and take off the fan cover.

Fan cover

[G] Middle cooling fan

(1) Open the front cover. Take out the toner bag,

toner cartridge, developer unit and cleaner unit.

(2) Take off the paper receiving tray and tray back

cover.


tor. Take off the bracket and cover plate of the

toner cartridge drive unit.

(4) Remove 3 screws and 3 washers.

Disconnect 2 connectors and take off the

exhaust fan and sub-separation fan.

Note: Pay attention to the direction of the air flow

when attaching the fan.FLO

W

FLOW

Sub-separation fan Exhaust fan

[Rear side]

[Front side]

Cover plate

Connector

BracketCover plate


(4) Remove 2 screws and take off the toner bag

holder.

Toner bag holder

(5) Take off the rear side upper and lower covers.

(6) Disconnect the developer bias connector of the

high-voltage transformer.

(7) Remove one screw and take off the developer

unit guide.

(8) Remove 2 screws and take out the middle cool-

ing fan duct.

Developer bias connector

Developer unit guide

Middle cooling fan duct

High-voltage transformer


(9) Remove 2 screws and take off the middle cool-

ing fan.


when attaching the fan.

Middle cooling fan

[H] Developer unit cooling fan



tor. Take out the developer unit cooling fan unit.

(3) Remove 2 screws and take off the duct cover.

(4) Remove the developer unit cooling fan.


when attaching the fan.

Developer unit cooling fan unit

Duct cover

Developer unitcooling fan

Connector


[J] Toner bag full detection sensor


(2) Take out the developer unit cooling fan unit.

(3) Take out the main motor, registration clutch and

gear unit.

( Chapter 10.4)


tor. Take out the toner bag full detection sensor


(3) Remove the discharge lamp.

Discharge lamp


and take out the toner bag full detection sensor.

Toner bag fulldetection sensorConnector

Toner bag full detection sensor

Latch

[I] Discharge lamp

(1) Take out the developer unit and cleaner unit.


tor. Take out the discharge lamp unit.

Connector

Connector

December 2000 © TOSHIBA TEC 12 - 1 DP4500/3500 DEVELOPMENT SYSTEM

12. DEVELOPMENT SYSTEM

12.1 ConfigurationDevelopment system consists of the following unit and components.

• Toner cartridge/toner cartridge detection switch

• Humidity sensor

• Drive unit for toner cartridge

• Developer unit Developer material

Mixers -1 and -2

Developer sleeve (magnetic roller)

Doctor blade

Auto-toner sensor

Drum thermistor

Drum

Doctor bladeMixer-2

Developer sleeve

Mixer-1

Auto-toner sensor

[Sectional view of developer unit]

Drum thermistor

DP4500/3500 DEVELOPMENT SYSTEM 12 - 2 December 2000 © TOSHIBA TEC

12.2 Functions(1) Toner cartridge/toner cartridge detection switch

The toner cartridge is filled with toner. The toner motor drives the cartridge to supply the toner to the

developer unit.

The toner cartridge detection switch detects whether the toner cartridge is installed.

(2) Drive unit for the toner cartridge

The toner motor rotates to drive the toner cartridge.

(3) Developer unit

a. Developer material

The developer material is made of a mixture of the carrier and toner.

The carrier is an electrical conductive ferrite whose size is 30 to 100µm. The toner is a resin particle

whose size is 5 to 20µm.

The developer material needs periodic replacement since its quality is deteriorated by long use.

b. Mixers-1 and -2

Friction is generated by mixing the developer material. The carrier is charged to (+) and the toner to

(–), and the image is formed on the drum surface by the static electricity caused by the friction.

c. Developer sleeve (Magnetic roller)

This is an aluminum roller with a magnet inside. The magnet works to suck the developer material

and forms the magnetic brush. The magnet is fixed at a position and the sleeve around it is rotated.

This rotation makes the magnetic brush of the developer sleeve sweep over the drum surface and

perform development.

d. Doctor blade

Doctor blade controls the amount of the developer material transported by the developer sleeve so

that the magnetic brush of the developer material contacts with the drum surface properly.

e. Auto-toner sensor

The carrier and the toner (toner density) in the developer material should be always fixed to a

certain ratio to output normal images. The auto-toner sensor detects the inclusion ratio of the toner

in the developer material by using a magnetic bridge circuit. When the quantity of toner gets short,

the toner motor is driven to supply the toner from the toner cartridge.


12.3 Drive Circuit of Toner MotorThe toner motor (brush motor) is a motor to supply toner to the developer unit.

The toner motor is driven by the transistor TA8428 (logic PC board: IC41).

Circuit diagram of the toner motor

Motor driver TA8428 (IC41) is connected with both ends of the motor wire.

— When the PD6(TNRMT-1A) of the G/A becomes “L” and PD7 (TNRMT-0A) becomes “H” levels, current

flows into the motor wire and the motor is rotated.

— When both of PD6 (TNRMT-1A) and PD7 (TNRMT-0A) of the G/A become “H” level, the motor is braked

and stopped.

— When both of PD6 (TNRMT-1A) and PD7 (TNRMT-0A) become “L” level, the motor waits for the next

command (the motor is stopped).

MAIN

-CPU

IC13

G/A

IC10

TD62385

IC28

TA8428

IC41

PD6 1

2

3

5

R344

PD7

Toner motor


BC-RAMIC40

CPUIC10

GAIC30

PWA-SYS

PWA-LGC

CPUIC13

95C063F

GAIC10

LCA301IC31

MB88347

TA8428IC41

12.4 Auto-Toner Circuit12.4.1 General description

(1) Function of the auto-toner circuit

· Detects the toner density in the developer material, and supplies toner when the density is lowered to

a certain level.

· Detects that there is no toner left in the cartridge (toner-empty detection).

(2) The auto toner circuit consists of the following:

· Auto-toner sensor : Detects the toner density.

· Control section : Controls the toner density so that the toner in the developer material is fixed to

certain ratio.

· Toner motor : Supplies toner to the developer material.

· Display : Indicates toner-empty information.

Display panel

Toner cartridge

Toner Tonermotor

Auto-toner sensor

Developer material

Controlvoltage signal

Control panel

Developer unit

D/Aconverter

Arithmetic and control unit

MAIN


12.4.2 Function of auto-toner sensor

(1) Function

a. Initialization adjustment function —At the first use of the copier or when the developer material is


Automatically adjusts the output value of the auto-toner sensor responding to humidity (input value

to the main CPU) for the toner density of the new developer material so that it stays in range of 2.35

to 2.45V.

b. Stabilizing the toner density —During the copying operation

Maintains the toner density to a certain ratio as follows.

Toner is consumed.

nThe toner density is lowered.

nChange in the auto-toner sensor output responding to humidity is detected.

nThe toner motor is driven.

nToner is supplied from the toner cartridge to the developer unit.

c. Toner-empty detection and recovery:

Detects that there is no toner in the toner cartridge:

The toner motor is driven.

nThe auto-toner sensor output does not change.

nThe toner density does not change.

nIt is determined there is no toner in the cartridge (toner empty).

Recovering from the toner-empty state:

The toner motor is driven.

nToner is supplied.

nThe auto-toner sensor output changes.

nThe toner density returns to normal value.

nThe toner-empty state is cleared.


(2) Function of auto-toner sensor

The auto-toner sensor consists of the following circuits:

· Drive winding : A magnetic head (primary side) with a high-frequency magnetic field, which

forms a magnetic circuit in the developer material.

· Detection winding : Receives the change in the magnetic resistance of the developer material

through the magnetic circuit (secondary side).

· DC conversion circuit : Converts a high-frequency output from the detection winding into a DC signal

(auto-toner output VATS

).

When the toner density is low—

The ratio of the toner against the carrier in the developer material decreases.

nThe magnetic resistance decreases.

nThe detection output increases.

nThe auto-toner output VATS

increases.

When the toner density is high—

The ratio of the toner against the carrier in the developer material increases.

nThe magnetic resistance increases.

nThe detection output decreases.

nThe auto-toner output VATS

decreases.

Magnetic resistance

Drivewinding

(Developer material)

Magnetic circuit

Detectionwinding

DCconversion

circuit

Auto-toneroutput

To the mainCPU (LGC)

VATS


12.4.3 Adjustment using the humidity sensor

Variation in the output of the auto-toner sensor due to humidity is corrected using the humidity sensor to

maintain the toner density in the developer material at a certain amount. The feedback control function

using the humidity sensor is applicable to the main charger grid, developer bias and laser power as follows.

The feedback control function can be set in the setting mode [0] + [8].

: Function effective —: Function ineffective

Code setting

08/839=0 (default)

08/839=1

08/839=2

08/839=3

Control of the auto-toner outpout VATS

—

—

Control of the main charger grid,

developer bias and laser power

—

—


12.5 Disassembly and Replacement[A] Developer unit

(1) Open the front cover and take out the toner bag.

(2) Loosen one blue screw and disconnect one con-

nector.

Take out the developer unit.

[B] Developer material

(B-1) Disposition of developer material

(1) Remove the top cover. (Release the protrusions

and latches, and slide the cover in the direction

of the arrow to take out the cover.)

(2) Incline the developer unit and remove the de-

veloper material from the part shown with the

arrow.

(B-2) Filling developer unit with developer mate-

rial

(1) Remove the lid of the developer bottle and fill

the developer unit with the developer material.

(2) Rotate the gear at the rear side manually in the

direction of the arrow to spread out the devel-

oper material over the developer sleeve.

Note: Securely attach 4 latches and 2 protrusionsat both sides of the cover when fixing thetop cover.

Connector

Latch

Protrusion

Protrusion

Top cover


[C] Guide roller

(C-1) Front side

(1) Remove the developer material.

(2) Make a note of the position which the polarity

adjustment lever is pointing at. (Mark the posi-

tion if needed.)

(3) Remove 3 screws and take off the front cover

of the developer unit.

(4) Remove one screw and take off the polarity ad-

justment lever.

(5) Remove one E-ring and take off the guide roller.

Note: Match the polarity adjustment lever with the

previously marked position on the scale

when assembling the guide roller.

(C-2) Rear side

(1) Remove 2 screws and take off the metal plate.

Scale Polarity adjustment lever

Front cover

Guide roller E-ring

Polarity adjustment lever


(2) Remove one E-ring and 4 gears.

(3) Take off the guide roller.

[D] Auto-toner sensor

(1) Dispose of the developer material.


tor. Take off the auto-toner sensor from the bot-

tom side of developer unit.

[E] Drum thermistor

(1) Take off the front cover of the developer unit.

(2) Remove 2 screws and take off the developer

sleeve cover.


tor, and take off the drum thermistor.

Guide rollerGear

E-ring

Connector

Developer sleeve cover

Connector


[F] Developer sleeve


(2) Take off the developer sleeve cover.

(3) Take out the guide rollers (front side and rear

side).

(4) Remove 2 screws from the front and rear sides.

Take out the developer sleeve unit lifting up both

sides of the shaft.

(5) Remove 4 screws and take off the doctor blade.

(6) Take off the developer sleeve.

(7) Replace the oil seal of the shaft at the rear side

of the developer sleeve with a new one.

( “Replacement of Oil Seal” described later)

u

Doctor blade

Developer sleeve

Oil seal


Note: 1. Make sure that the side seals (urethane

seal) of the front and rear sides do not

come out of the case when assembling

the developer sleeve unit (see the figures

below).

2. Make the gap adjustment of the doctor-

sleeve when assembling the doctor blade.

[Front] [Rear]

Side seal

Toner scatteringpreventionsheet

Side seal

Toner scatteringpreventionsheet

[G] Mixer-1


(2) Take out the developer sleeve unit.

(3) Remove one E-ring at the rear side, the bushing

(plastic) at the front side and the bushing at the

rear side. Take off mixer-1.

(4) Replace the bushings and the oil seals on the

developer frame with new ones.


[H] Mixer-2


(2) Remove one E-ring and the bushings (rubber) at

the front side and the bearing at the rear side.

(3) Remove one screw and take off the holder for

mixer-2 at the front side.

(4) Take off mixer-2.

(5) Replace the oil seals on the holder and at the

rear side of the developer unit frame.


uu

[Rear side]

[G] Bushing [H] Bearing[G] E-ring

[Front side]

[H] Bushing (rubber) [H] Holder

[H] E-ring

[G] Mixer-1

[H] Mixer-2

[H] Mixer-2


[I] Drive unit for the toner cartridge

(1) Take out the toner cartridge.

(2) Take off the paper receiving tray and tray back

cover.

(3) Remove the metal cover of the toner cartridge

drive unit.

(4) Remove 2 screws and take out the drive unit for

the toner cartridge.


2. Push in new oil seal in parallel with the frame of

the developer unit or bushing of the mixer shaft

paying attention to its direction.

3. Apply grease (Alvania No.2; quantity like one

grain of rice) evenly over the entire surface of

the oil seal. Assemble the mixer and developer

sleeve.

Note: Wipe off excessive grease.

4. Apply grease (Alvania No.2; quantity like one or

two grains of rice) on the entire surface of the

shafts of the mixer and the developer sleeve

evenly, and attach the bushings.

(Bushing side)

Oil seal

Shaft

Wipe off

Grease

Grease

(Inside of frame)

<< Replacement of Oil Seals >>

Locations of the oil seals used in this developer unit (5 in total)

a. One at the rear side of the developer sleeve shaft

b. Two at both sides of the shaft of mixer-1

c. Two at both sides of the shaft of mixer-2

Procedure for replacement of the oil seal

1. Stick something thin like a screwdriver into the

depression of the oil seal to take it out.


[J] Toner car tridg e detection s witc h

(1) Open the front cover. Take out the toner bag and

toner cartridge.

(2) Remove 2 screws and take off the toner car-

tridge cover.


tor. Take off the toner cartridge detection switch

unit.

(4) Remove 2 screws and disconnect 2 connectors.

Remove the toner cartridge detection switch from

the bracket.

Toner cartridge cover

Connector

Tonercartridgedetectionswitch unit

Bracket

Connector

Toner cartridgedetection switch


[K] Humidity sensor

(1) Open the front cover and take out the paper re-

ceiving tray.

(2) Remove 4 screws and take off the metal cover

of the system unit.

(3) Disconnect one connector of the humidity sen-

sor.

(4) Remove the humidity sensor in the direction of

the arrow while the part of the holder indicated

as A in the right figure is slightly lifted up.

Metal cover

Connector

Humidity sensor window

Humidity sensor

A

December 2000 © TOSHIBA TEC 13 - 1 DP4500/3500 FUSER UNIT/PAPER EXIT UNIT

Exit roller Separation finger for thefuser roller

Separation finger for thepressure roller

Exit sensor

Fuser unit cooling fan

Cleaning roller

Pressure rollerIH coilFuser roller

Thermistor

Thermostat

13. FUSER UNIT/PAPER EXIT SECTION

13.1 General DescriptionThe toner is fused by applying heat and pressure on the paper separated from the drum. The paper is then

transported to the receiving tray through the paper exit section. The fuser unit consists of the IH coil, fuser

roller, pressure roller, separation fingers, cleaning roller, thermistors, thermostat, exit rollers, exit sensor,

etc.

13.2 OperationHeat and pressure are applied to the paper separated and transported from the drum to have the toner

fused onto the paper. The fuser roller and pressure roller are pressed to each other with the spring at a

certain pressure, and driven by the main motor. The fuser roller is rotated by the motor drive and it has an

IH coil inside which does not rotate.

After the fusing, the paper is separated smoothly from the fuser roller by the separation fingers. The

temperature of the fuser roller is controlled by a thermistor in the temperature detecting section. Power

supply to the IH coil is cut off by the thermostat when the temperature becomes abnormally high.

DP4500/3500 FUSER UNIT/PAPER EXIT UNIT 13 - 2 December 2000 © TOSHIBA TEC

13.3 Functions(1) IH coil (IH: Induction Heating)

The IH coil is in the fuser roller and applies the induction heating to the fuser roller. The coil is fixed at

a position and does not move when the fuser roller is rotating.

(2) Fuser roller

The fuser roller is made of the iron and induction-heated by the IH coil. The fuser roller is in contact with

the below-mentioned pressure roller, and fusing is performed by passing the sheet of paper between

these two rollers. At this time, the toner image on the paper faces the fuser roller. Toner is melted by the

heat of fuser roller while the heat conductivity is improved by the pressure from the pressure roller, and

the toner soaks into the fibers of the paper.

The surface of the fuser roller is coated with the fluoroplastic to prevent the toner from adhering onto

the roller ( the phonomenon called “offset”) and to help the separation of the toner from the fuser roller.

(3) Pressure roller

The pressure roller is made of the silicon sponge which is highly cohesive and always pressed against

the fuser roller by springs.

(4) Separation finger

The separation fingers for the fuser and pressure rollers separate paper adhering to the fuser roller and

pressure roller.

(5) Cleaning roller

A metal cleaning roller is attached in contact with the pressure roller to remove the toner and paper

scraps sticking to the pressure roller.

(6) Exit sensor

This sensor detects the arrival of the leading edge or trailing edge of paper at the exit roller of the fuser

unit. It is also used to detect paper jams in the fuser unit paper discharge area and of the trailing edge

of the paper turned over for duplex copying.

(7) Fuser roller center thermistor

The thermistor detects the temperature of the fuser roller to maintain it within a certain temperature

range (the actual temperature is around 180°C) which is higher than the lower limit (the temperature

which causes the poor fusing) and lower than the upper limit (the temperature which causes the toner

offset). Thus, the thermistor controls the temperature of the fuser roller to turn on the IH coil when it is

lower than the set temperature and turn it off when it is higher than that.


(8) Fuser roller side thermistor

The temperature distribution of the fuser roller may differ significantly at the center area and end area

in the lengthwise direction depending on the printing conditions. The side thermistor detects the tem-

perature of the end area. This center and side thermistors control the temperature to cut off the power

supply to the IH coil when either values detected by them exceeds the set temperature.

(9) Thermostat

The thermostat cuts off the power supply to the IH coil if the fuser roller becomes abnormally hot as a

result of any problems such as thermistor malfunction. The thermostat for this copier is used to prevent

abnormal operation. When the thermostat detects any abnormality, the thermostat must be replaced

together with the other damaged parts in the fuser unit.


13.4 Heater Control Circuit13.4.1 Configuraton

[Blo

ck d

iagr

am o

f fus

er u

nit a

nd IH

con

trol

circ

uit]

NL

CP

U

LGC

IH

5V S

W

5V S

W

Sid

eth

erm

isto

r

Cen

ter

ther

mis

tor

Fus

er r

olle

r

The

rmos

tat

Co

il

Pow

er c

ode

Bre

aker

No

ise

filte

r

Fus

e

AC

inpu

tC

oil

outp

ut IH p

ower

sou

rce/

driv

e ci

rcui

t

Con

trol

circ

uit

incl

udin

g C

PU

Pho

toco

uple

r

AC

lin

e

DC

lin

e

Pow

er s

uppl

y fo

rph

otoc

oupl

er

Ele

ctric

pow

er s

ettin

g

Err

or s

igna

l

IH O

N/O

FF s

igna

l (L:

ON

)

Dru

mth

erm

isto

r

Tem

pera

ture

cont

rol

circ

uit


13.4.2 Heating principle of IH heater

High frequency magnetic field is generated by applying a current of high frequency to the heating coil (IH

coil) in the fuser roller to produce the eddy current in the fuser roller.

Resistance element of the fuser roller generates Joule heat with which the roller is heated when the eddy

current flows in the fuser roller. The thermal efficiency is high because the fuser roller is directly heated by

the heater.

[Image of current flowing from A to B]

B

A

Current flowing on the surface of the fuser roller

High frequencypower source

IH coilHigh frequencymagnetic field

Eddy currentCurrent flowing inside thefuser roller

[Block diagram of high-frequency power supply]

D1

T1

C1

C2

CPU

Te1(IGBT)

IGBTdrive

IH coil

Fuser roller

Monitoring input current

Monitoring input current

Current input

Voltageinput I/F circuit on LGC board

Pho

toco

uple

rSmoothing circuit

Control circuit for high-frequency current


13.4.3 IH control circuit interface

The IH control circuit uses a photocoupler as insulation against the secondary circuit.

The interface signals are as follows.

(*Note) IH status signal

• When the temperature (due to insufficient cooling) of the switching element (IGBT) is abnor-

mal:

“10: Abnormal temperature, IH-FAN stopped” n After a certain period of time n Error[C48]

• When the upper limit of the power voltage is abnormal: “00: Initializing” n After a certain

period of time n Error[C47]

• When the lower limit of the power voltage is abnormal: “00: Initializing” n After a certain

period of time n Error[C47]

• Defective circuits n: “11” Abnormal circuit, defective coil n Error[C49]

• Standby state after initialization: “01: Ready”

No. Name of signal Direction Definition

J522-1 5V

J522-2 PWR3 Host to IH

J522-3 PWR2

J522-4 PWR1

J522-5 IH ON/OFF Host to IH Thermistor monitoring feedback signal from host

J522-6 ERROR2 IH to Host IH status signal (*Note)

J522-7 ERROR1 (ERROR2 ERROR1)

J522-8 GND


13.4.4 Relation between system configuration and IH output

* FIN: Finisher, FAX: Fax unit, PRT: Printer unit, SC: System controller

(*1) The electric power is lowered when a document fed from the ADF is scanned while the copier is

warming up.

(*2) AC power should be 100V when the copier is warming up (the lower the voltage, the longer the

warming up time becomes).

13.4.5 Abnormality of IH control circuit

IH output is stopped when the IH control circuit does not work properly.

(1) When the power voltage of the copier is too high or too low

IH output is stopped to protect the IGBT when the input voltage which is higher or lower than specified

range is applied to the copier. This is an error [C47].

(2) When the AC is not applied to the IH control circuit

The AC is not applied to the IH control circuit properly. This is an error [C47]. The same error occurs

when the thermostat is activated (blown).

(3) When the temperature of the IGBT is too high

IGBT is forcibly cooled down by the fan as it becomes hot when the power is supplied to the IH control

circuit. The error [C48] is occurs when the cooling operation is not sufficient and the IGBT gets too hot.

System configuration Warming up Ready CopyingEnergy Automatically Warming

saver mode OFF up time

Copier only 1300/1250W 700W 900W 700W OFF Approx.

Copier and ADF(*1) 1250/1200W(*2) 30 sec.

Copier, ADF(*1) and FIN 1250/1200W Approx.

Copier, ADF(*1) and FAX 1200/1100W(*2) 40 sec.

or

Copier, ADF(*1), FAX

and PRT

Copier, ADF(*1), FIN, 1200/1100W Approx.

FAX and PRT 45 sec.

Copier, ADF(*1) and SC

Copier, ADF(*1), FIN, 1100/1100W Approx.

FAX and SC 50 sec.


(4) The temperature detection sensor of the IH control circuit is malfunctioning

The error [C49] occurs when the temperature detection sensor of the IH control circuit does not work

properly.

The same error code is displayed in case the IH coil is not connected properly.

13.4.6 Temperature detection section

To keep the fuser roller temperature constant, the thermistors detect the temperature and control ON/OFF

of the heater. Output from the thermistors is used to detect abnormality.

(1) Relation between the thermistor output voltage and surface temperature of the fuser roller:

Approx. 4.0V when the temperature is 200°C, and approx. 0.5V when the temperature is 40°C.

Approx. 3.7V when the temperature is 180°C, and approx. 3.9V when the temperature is 190°C.

(2) Control of the surface temperature of the fuser roller:

C

190180

OFF ON OFF ON OFF ON OFF ON OFF OFFON

(3) Temperature control for both ends of the fuser roller

During the multiple copying, the temperature of both ends of the fuser roller (areas where the paper

does not pass) generally tends to become higher than that of the other areas (areas where the paper

passes). The temperature of the ends is detected by the side thermistor, and when it reaches 250°C,

the heater is automatically turned OFF regardless of the temperature of the area where the paper

passes.

(4) Error detection during warming up (1)

If the output voltage of the thermistor does not go over approx. 0.5V(40°C) even a certain period of time

has passed after the heater was turned ON, service call [C41] is displayed.


If the output voltage of the thermistor does not go over approx. 3.2V(150°C) after it exceeded 40°C and

a certain period of time has passed, service call [C44] is displayed.

Warming-up Ready (190°C) During copying (180°C)

Temperatureof fuser roller

Heater ON


(6) Error detecion during standby and copying

Service call [C43] is displayed if the output voltage of the center thermistor becomes approx. 0.5V or

lower for 0.5 sec. or longer. If the side thermistor is in this condition, service call [C45] is displayed.


If the output voltage of the thermistor does not go over approx. 3.9V(190°C) after it exceeded 150°C

and a certain period of time has passed, service call [C44] is displayed.

(8) Thermistor/heater status counter control

• To enhance the safety of the fuser unit, the CPU provides the following protection: When the third

[C41] error has occurred after two consecutive [C41] errors, even if the operator turns the power OFF

and then back ON, the heater is not turned ON and error [C41] is displayed immediately.

However, if the copier becomes ready normally with the thermistor/heater status counter “1” or below,

the counter is cleared to “0”.

• If the heater is not turned ON and any of the error codes [C41] to [C45] is still displayed even though

the thermistor, thermostat and IH coil have been repaired and the power is turned ON, check the

code “400” in the mode (08) to set the thermistor/heater status counter to “0”.

Reference

* The thermistor/heater status counter never has values other than 0 ~ 19 entered.

• If the heater does not come ON and service call [C41] is displayed immediately after the power

is turned ON, check the thermistor/heater status counter. If it is “2” or over, be sure to check the

thermistor, thermostat and IH coil. Reset the counter to “0” (code “400” in the (08) mode) after

repairing them, then turn ON the power.

• If the thermistor/heater status counter is “20” or over (e.g., 21), there is a possibility that data in

BCRAM or BCRAM itself may have been ruined due to causes such as leakage from the charg-

ers. Check the bias, high-voltage transformers and charge wires to see if any of them is defec-

tive, and also look through all the data in the BCRAM.


13.4.7 Detection of open-circuited thermistors

A thermistor is a device whose resistance decreases when it detects high temperature. If the fuser roller

thermistor is open-circuited, the control circuit determines that the fuser roller temperature is extremely

low, and keep turning ON the IH coil. As the result, the fuser roller temperature rises, possibly activating

the thermostat which is a safety protection device. To prevent this, CPU works to detect if the thermistor is

open-circuited or not.

* The following is a circuit diagram of the thermistor open-circuit detection circuit for the center thermistor.

The same circuit is used for the side thermistor.

· The input voltage is obtained by dividing the resistor-1, thermistor, resistor-2 and resistor-3.

· The surface temperature of the fuser roller changes.

x

The resistance of the thermistor changes.

x

The input voltage changes.

· The main CPU detects this change of the input voltage to determine if the thermistor is abnormal or not.

Center thermistor

Main CPUR165

+5

R170

R174

C125

HTRTH-

Resistor-1

Resistor-2

Resistor-3


13.4.8 Control for abnormal heater conditions

The heater cannot be turned ON/OFF when trouble occured to the IH control circuit. In this case, the

microcomputer detects abnormal temperature using the center and side thermistors, determines the corre-

sponding error codes and counter values. The power is then turned OFF to protect the fuser unit in case the

machine is 200V-series.

(1) Temperature to be detected

Abnormal temperature detected by the thermistors:

Center thermistor: 230°C

Side thermistor: 270°C

(2) Error code

[C44] “Call for service” : Displayed when the keys [C/S] and [8] are pressed simultaneously.

Counter value “9” : Displayed by entering the code number “400” in the setting mode (08).

(3) Operation of the machine

The microcomputer stops the output of the heater, exposure lamp, control panel display and motor,

then turns OFF the power in case the machine is 200V-series.

(4) Corrective action

[For 200V-series]

Thermistors continue detecting the abnormal temperature even after the error codes and counter val-

ues are determined. Even if the power is turned ON by the operator, it is automatically turned OFF

when the surface temperature of the fuser roller is still abnormal or higher than the temperature in (1).

This behavior is repeated until the temperature becomes normal.

Wait until the surface temperature of the fuser roller is lowered enough, and turn ON the power to check

the counter value.

[For 200V-series and other models]

The copier is returned to the normal conditions by fixing the heater and setting the counter value of the

setting code from “400” to “0”.


13.5 Exit Motor DriveThe control circuit of the exit motor which works to drive the exit roller is shown below.

The exit motor is a 4-phase control PM stepping motor. The motor is turned ON/OFF and the direction of its

rotation is changed by controlling the timing of the pulse signal output (A·A·B·B).

+24A

PWA-F-LGC-320

CPUIC13

Exitmotor

MotordriverIC35

EXTMA-0

EXTMB-0

EXTMC-0

EXTMD-0

A

B

A

B


13.6 Disassembly and Replacement[A] Fuser unit


upper cover.

(2) Disconnect 2 connectors and 2 faston terminals.

(3) Open the jam access cover.

(4) Remove 2 blue screws and take out the fuser

unit.

[B] Fuser unit cooling fan

(1) Release the hooks near the hinges and take off

the fuser unit cover.

Connector and faston terminal (2 each)

Jam access cover

(2) Disconnect one connector, remove 2 screws and

release 2 latches. Take off the fuser unit cooling

fan.

(3) Release 2 latches and remove the fan cover.

(4) Release the harness from the holder.

Remove 4 screws and take off the fuser unit

cooling fan.

Connector

Latch

Latch

Fan cover

Fuser unit cover Hook


[C] Exit sensor

(1) Remove 2 screws and open the upper exit unit

(2) Release the latches and remove the exit sensor

cover.


and remove the exit sensor.

Exit sensor coverUpper exit unit

Connector

Exit sensor

[D] Exit finger

(1) Pull out the shaft and remove 8 exit fingers.

[E] Separation finger for pressure roller

(1) Remove 5 separation fingers for the pressure

roller.

[F] Separation finger for fuser roller

(1) Remove 2 screws and take out the lower paper

exit unit.

Exit finger Shaft

Separation finger for pressure roller

Lower paper exit unit


(2) Remove 6 separation fingers for the fuser roller.

[G] Cleaning roller

(1) Remove one screw and take off the rear side

cover.

Separation fingerfor fuser roller


(2) Remove the screws from the front and rear sides

(2 each). Take off the stay of the pressure roller

side.

(3) Remove the E-ring. Take off the cleaning roller

together with the bushings at the both sides.

Stay

Cleaning rollerBushing

E-ring

[Rear side]

[Front side]


[H] Pressure roller

(1) Take off the pressure springs of the front and

rear sides from the hooks.

(2) Take off the pressure roller.

[I] IH coil

(1) Remove 2 screws and take off the front coil

holder.

(2) Remove one screw and take off the rear coil

holder.

Pressure spring

Pressure roller

Front coil holder

Rear coil holder


(3) Pull out the IH coil from the rear side.

[J] Fuser roller

(1) Remove the grip ring of the front side.

(2) Remove the E-ring of the rear side and take off

the gear A.

(3) Remove the grip ring and gear of the rear side.

(4) Take off the fuser roller.

Notes: 1. Do not deform the thermistor when

installing the fuser roller.

2. Pay attention to the direction of the gear

(the position of a square protrusion on the

inner face of the gear) when attaching it.

IH coil

Fuser rollerGrip ring

[Front side]

[Rear side]

Grip ringGearFuser roller

Gear A

Outer edge(Grip ring side)

Protrusion

Inner edge(Bearing side)


[K] Thermistor

(1) Remove one screw and take off the center ther-

mistor.

(2) Remove one screw and take off the side ther-

mistor.

Note: Do not deform or damage the thermistors

and frame (metal sheet) when fixing the

thermistors.

[L] Thermostat

(1) Remove 2 screws and take off the thermostat.

Sidethermistor

Center thermistor Thermostat

Notes: 1. Give attention to the order to fix the ther-

mostat terminal and harness terminal

when fixing the thermostat with a screw.

2. Adjust space between the fuser roller and

thermostat by tightening/loosening the

screw A while the pressure roller is

pressed against the fuser roller to make

the space fall within 1.5 to 1.9mm.

[M] IH control board cooling fan



Take off the IH control board cooling fan together

with the sheet metal.

(3) Remove 2 screws and take the IH control board

cooling fan apart from the sheet metal.


from the fan when installing it.

IH control board cooling fan

Connector

Screw A

Harness terminalScrew Thermostat


[N] IH control board


Take off the IH control board.

[O] Exit motor

(1) Remove 2 screws and take off the case of the

IH control board (Slide the case to the right to

detach the hooks, then take off the case).

Note: If the IH control board is not replaced with

new one, the board does not have to be sepa-

rated from the case.


Take off the exit motor behind the sheet metal


(3) Remove 2 screws and take off the exit motor.

ConnectorIH controlboard

Connector

Exit motor

[O]

[O]

December 2000 © TOSHIBA TEC 14 - 1 DP4500/3500 AUTOMATIC DUPLEXING UNIT

14. AUTOMATIC DUPLEXING UNIT (ADU)

14.1 General DescriptionThe Automatic Duplexing Unit (ADU) is a unit which automatically makes a copy on both sides of a sheet

of paper.

The switchback method is adopted for the ADU of this model.

The sheet of paper is switchbacked right after the copying operation (fusing process) on one side is

completed, and the reversed paper is transported to the registration section to be copied on another side.

The ADU mainly consists of the transport rollers and their drive system, paper transport guide and the

ADU entrance/exit sensors.

Lower transport roller

Exit guide

ADU exit sensor

ADU motor

Middle transport roller

ADU entrance sensor

Entrance guide

Upper transport roller

Paper guideExit gate

DP4500/3500 AUTOMATIC DUPLEXING UNIT 14 - 2 December 2000 © TOSHIBA TEC

14.2 Description of OperationsThe back side copying (data for the back side of a paper is recorded) is performed by first selecting the

duplex copying mode and pressing the START key. When the trailing edge of the paper passes the exit

gate, the paper is switchbacked and transported to the ADU (the exit gate is closed by its own weight) then

to the registration section, and the front side copying (data for the front side of the paper is recorded) is

performed. The paper passes through the exit gate again and is transported to the paper receiving tray to

complete duplex copying.

There are three kinds of jams which are related to the ADU.

E51: The ADU entrance sensor does not come ON within a fixed time after the switchback operation has

been started in the ADU.

E52: The ADU exit sensor does not come ON within a fixed time after the ADU entrance sensor has

become ON.

E11: The registration sensor does not come ON within a fixed time after the ADU has started feeding paper

into the main unit.

The error [E43] occurs if the ADU is opened during duplex copying. The ADU motor and ADU clutch are

stopped at this time.

If the copying operation is interrupted or stopped for some reason other than jam or service call, the

process in progress on a sheet of paper is completed and the sheet is discharged into the paper receiving

tray.

The operation of the duplex copying varies depending on the size of the paper: Single-sheet circulation and

Double-sheet circulation.

The figure on the following pages show the duplex copying operation when documents from page one to

four are copied. The numbers in the figure indicate the page numbers.


(a) Single-paper circulation

With sheets of paper other than A4/LT size, duplex copying (back-side copying n front-side copying) is

performed for a single sheet of paper as shown below.


(b) Double-sheet circulation

With A4/LT sized paper, duplex copying is performed for two sheets of paper at a time as shown below. The

sheets are processed in the following order.

Back side of the 1st sheet n back side of the 2nd sheet n front side of the 1st sheet n front side of

the 2nd sheet


2236

326

204

1262

036

220

3222

6823

0024

30

4382

4560

3826

6640

7036

8060

9010

9354

1055

812

432

5708

7096

8060

9010

9354

1128

212

432

4970

6916

7580

1053

411

696

1274

0

5304

6602

7910

1112

212

030

5718

5942

7642

7762

2272

3480

4490

6670

7680

7982

8992

1028

811

298

1249

413

504

2018

2226

4236

5900

8738

2204

2394

4420

5632

7606

7726

8926

9278

1122

412

356

1343

0

3320

4460

5532

7650

8716

8962

1004

011

264

1234

413

470

1453

8

Timing chart for duplex copying on 3 A4 sized sheets fed from the upper cassette

In t

he m

ain

unit

Exi

t se

nsor

Reg

istr

atio

nse

nsor

Upp

er c

asse

ttefe

ed s

enso

r

Reg

istr

atio

ncl

utch

Tran

spor

t cl

utch

(low

spe

ed)

In th

e A

DU

AD

U e

ntra

nce

sens

or

AD

U e

xit

sens

or

AD

U c

lutc

h

AD

U m

otor


Timing chart for duplex copying on one A3 sized sheet fed from the upper cassette

In t

he m

ain

unit

Exi

t se

nsor

Reg

istr

atio

n se

nsor

Reg

istr

atio

n cl

utch

In th

e A

DU

AD

U e

ntra

nce

sens

or

AD

U e

xit

sens

or

AD

U c

lutc

h

AD

U m

otor

975

1920

019

80

4110 42

70

3550

5425

5485

6860

5425

5485

6860

4690

6680

6000

5485

7465

5345

7380

3035

6445

8500


14.3 Drive of ADUWhen the ADU motor rotates in the direction A, the upper transport roller is rotated driven by the gears and

belt. The ADU clutch is then turned ON, allowing the middle transport roller and lower transport roller to

rotate.

Upper transport roller

Middle transport roller

ADU motor

ADU clutch

Lower transport roller

A


14.4 Flow Chart

Yes

No

Yes

No

Yes

A

No

Exit motor reverserotation ON

400msec. elapses

ADU motor ON

ADU entrancesensor ON?

ADU transport jam(E51)

32msec. elapses(A sheet is transported to the positionwhere the sheets are stopped first.)

The trailing edgeof the first sheet turned

ON the ADU exitsensor?

ADU motor stopped

ADU motor ON

ADU clutch ON

ADU exit sensor ON?

400msec. elapses

ADU transport jam(E52)


Yes

No

Yes

No

A

ADU paper feedingcommand signal

received

ADU motor stoppedADU clutch OFF

ADU motor/clutch ON

ADU feedingoperation started

Registrationsensor ON?

ADU misfeeding(E11)

Registrationproceeded

Registration operationcompleted

ADU motor stoppedADU clutch OFF

Next paper is readyfor the registration


14.5 Disassembly and Replacement[A] ADU

(1) Remove the feed side rear hinge cover and feed

side front hinge cover.

(2) Open the ADU.

(3) Disconnect one connector and remove one screw

fixing the ground wire. Remove the pin.

(4) Slide the ADU to the rear side and take it off.

[B] ADU inside cover

(1) Remove 2 screws and take off the ADU inside

cover (front).

(2) Remove 2 screws and take off the ADU inside

cover (rear).

[C] ADU opening/closing switch


and take off the ADU opening/closing switch.

[D] ADU cover

(1) Remove 4 screws and take off the ADU cover.

Note: Make sure to attach the ADU opening/clos-

ing switch when attaching the ADU cover.

ADU inside cover (rear) ADU inside cover (front)

Connector

Pin

ADU opening/closing switch


[E] Paper guide

(1) Detach the fulcrum at the rear side from the

frame.

Take off the paper guide.

(2) Release the hook springs and remove the pinch

rollers (6 each).

(3) Remove 2 screws and take off 2 pressure plate

springs.

[F] Latches

(1) Remove the spring.

(2) Remove one screw and take off the front latch.

(3) Remove the screw and take off the rear latch.

Front latch

Spring

Rear latch

Pressure plate spring Pinch rollerHook spring

Fulcrum


[G] Opening/closing lever

(1) Remove 2 screws and take off the opening/clos-

ing lever.

[H] ADU entrance sensor and ADU exit sensor


and remove the ADU entrance sensor.


and remove the ADU exit sensor.

[I] ADU board

(1) Remove 4 screws and take off the bracket. Dis-

connect one connector of the harness connected

with the ADU board from the bracket.

Opening/closing lever

Lock supportADU board

ADU motor

(2) Disconnect 5 connectors. Release 4 lock sup-

ports and take off the ADU board.

[J] ADU motor

(1) Remove 2 screws and take off the ADU motor.

ADU entrance sensor

ADU exit sensor

Bracket


[K] ADU drive unit

(1) Remove 3 screws and take off the gear unit.Gear unit

(2) Remove 2 E-rings and take off 3 gears.

(3) Disconnect one connector. Loosen one setscrew

and take off the ADU clutch.

[L] ADU transport rollers and entrance/exit guides

(L-1) Upper transport roller


E-ring

Connector

Setscrew


(2) Remove the clip of the front side.

(3) Remove the clip, pulley, fixing pin and belt of

the rear side.

(4) Remove 2 bushings and take off the upper

transport roller.

(L-2) Middle transport roller


the front side.

(2) Remove the clip of the rear side.

(3) Remove 2 bushings and take off the middle

transport roller.

(L-3) Entrance guide

(1) Remove 4 screws (2 each for front and rear sides)

and take off the entrance guide.

(L-4) Lower transport roller


the front side.

(2) Remove the clip of the rear side.

(3) Remove 2 bushings and take off the lower

transport roller.

(L-5) Exit guide

(1) Remove 3 screws (2 for the front side and 1 for

the rear side) and take off the exit guide.

[Front side]

[Rear side]

[Front side]

[Rear side]

Bushing (L-4)

Clip (L-4)

(L-5)

Clip (L-1)

Bushing (L-1)

Clip (L-2)

Pulley (L-2)

Bushing (L-2)

(L-3)

(L-3)

Fixing pin(L-2)

Bushing(L-4)

Pulley (L-4)

Exit guide

Clip (L-4)

(L-5)

(L-5)Fixing pin(L-4)

Bushing(L-1)

Pulley (L-1)

Clip (L-1)

Entrance guide

(L-3)

(L-3)

Clip (L-2)

Bushing (L-2)

Fixing pin (L-1)

December 2000 © TOSHIBA TEC 15 - 1 DP4500/3500 POWER SUPPLY UNIT

15. POWER SUPPLY UNIT

15.1 ConfigurationThe power supply unit consists of an AC filter and insulation type DC output circuits.

(1) AC filter

Eliminates noise from the outside and prevents noise generated by the copier from leaking to the outside.

(2) DC output circuits

The DC outputs are roughly divided into three lines of outputs:

a. System line : Power supply used around-the-clock mainly for the SYS/FAX board. This line outputs

three voltage (+3.3V, +5.1V, +12V) which start up when the main switch is turned ON.

b. Main line : Power supply used in the entire machine during image forming process. This line

outputs four voltage (+3.3V, +5.1V, +12V and -12V) which are started up by the

signals from the SYS board.

c. Door switch line : Power supply used in the entire machine during image forming process, being sup-

plied via the door switch. This line outputs two voltage (+5V and +24V) which start up

when the door switch is turned ON and with the signals from the SYS board.

DP4500/3500 POWER SUPPLY UNIT 15 - 2 December 2000 © TOSHIBA TEC

15.2 Operation of DC Output Circuits(1) Start of operation

When the main switch of the copier is turned ON, AC power is supplied to the switching regulator-1 (REG

1) to start up three output voltage of the system line. System CPU is then activated to output the power

control signal (PWR-EN: “L” level), and four output voltage of the main line are started up. If the door switch

of the copier is ON (the door is closed) at this time, AC power is supplied to the switching regulator-2 (REG

2) to start up two output voltage of the door switch line.

(2) Stop of operation

When the main switch of the copier is turned OFF, the power-OFF signal (PWR-DN) is output (Hi-Z: High

impedance) after the instantaneous outage insurance time (20 msec. at least) has elapsed. After the

power-OFF signal has been output, the regulator-1 (system line and main line) retains the rated voltage for

the minimum retaining time (15 msec. at least, depending on the AC input and load capacity), then starts

to drop the voltage.

(3) Output protection

Each output system includes an over-current protection circuit (which has the fuse protecion and the series

regulator internal protection functions) and an over-voltage protection circuit (does not cover the voltage

±12V of the system/main lines). These circuits prevent the abnormal operation or damage to the secondary

circuit caused by over-current due to shorted load or over-voltage due to short-circuit between different

voltages.

When the protection circuit is activated, remove the causes such as short-circuits (replace the fuse if it is

blown), and turn ON the power again to clear the circuit. Occasionally it may not cleared when the power is

turned back ON too soon (within 30 seconds).


15.3 Output ChannelThe following are 3 output channels which are not linked with the door switches.

(1) 3.3V

3.3VA : Pin 1, J412

Output to the LGC board

3.3VB : Pins 1, 2 and 3, J413

Output to the SYS board

3.3VC : Pin 1, J414

Output to the SLG board and CCD board via SLG board

3.3VD : Pin 4, J413


(2) 5.1V

5.1VA : Pins 3 and 4, J412


5.1VB : Pins 17, 18, 19 and 20, J413


5.1VC : Pin 21, J413


5.1VD : Pins 3 and 4, J414

Output to the SLG board, SDV/CCD board (via SLG board) and FUS board

5.1VE : Pin 5, J414

Output to the RADF and finisher

5.1VF : Pin 6, J414


(3) 12V

12VA : Pin 24, J413


-12VA : Pin 26, J413


12VB : Pin 25, J413


12VC : Pin 11, J414

Output to the SLG board and CCD board via SLG board


The following are 2 output channels which are linked with the door switches.

(1) 5.1V

5.1VG : Pin 5, J416


(2) 24V

24VC : Pin 1, J415

Output to the SLG board and SDV board via SLG board

24VD : Pin 2, J415


24VE : Pin 3, J415


24VF : Pin 1, J416

Output to LGC board (MOT, FAN, ADU and CLT)

24VG : Pin 2, J416

Output to LGC board (MOT, FAN, relay unit and high-voltage transformer)

<<Output connector>>

Not linked with the door switches

J412 for the LGC board

J413 for the SYS board

J414 for the SLG board, SDV board, RADF and finisher

Linked with the door switches

J415 for the SLG board, SDV board, RADF and finisher

J416 for the LGC board, MOT, FAN, ADU, CLT, relay unit and high-voltage transformer


[Configuration of power supply unit]

Noisefilter

Noisefilter

Noisefilter

IH

REG2

F1

F2

F3

F4

F5

F6

F7

24VC (SCN)

5.1VGPWR-EN

24VD (RADF/FIN)

24VE (RADF/FIN)

24VF

24VG

REG1

3.3VA/5.1VA (M)

3.3VB.D/5.1VB, C (SYS)

3.3VC/5.1VD (SCN)

5.1VE, F (RADF/FIN)

12VA, B (SYS)

–12VA (SYS)

12VC (SCN)

PWR-DN

Breaker Main switch

Door switch

Switchingpower supply


AC input

ON (Instantaneous outage)

[Sequence of power supply]

Max. 20ms

OFF

120ms or lower

PWR-DNsignal

20ms or higher

50ms or higher500ms or lower

System lineoutput (withrated load)

200ms or lower

Lower limit of eachrated voltage or higher

Hi-Z(Highimpedance)

200ms or lower

PWR-EN signal

Main line outputDoor switch line output(with rated load)

(L)

Lower limit of eachrated voltage or higher

(L)

Hi-Z (High impedance)


(3) PWA-F-SLG-320

(4) PWA-F-CCD-320


(5) PWA-F-SDV-320

(6) PWA-F-LDR-320

(7) PWA-F-SNS-320


(8) PWA-F-ADU-520-3

(9) PWA-F-FUS-320

dp3500-4500 sm.pdf

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