sappi technical series press troubleshooting

7/28/2019 Sappi Technical Series Press Troubleshooting

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On-Press TroubleshootingTips for solving problems on press andocumenting complaints

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On-Press Troubleshooting* J o I U I M l C O Oand documenting complaints

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Problems081012141618202224262830323436

IntroductionFor Your InformationTroubleshooting Guidel inesHickeysPick ing/Contaminat ionPilingDustSmashed BlanketScratches/Blade StreaksDelaminationMisregistrat ion/SlurBlocking/Offsett ingMott leBlisteringBaggy RollsWavy PaperDocumenting the ProblemComplaint Report

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No doubt, paper problems are a hassle. But they dohappen. And believe us, they are not something we atSappi endure lightly either.Our wish with this guide is to make troubleshootingas easy as possible for you. Consider this book areference. It is full of useful explanations and problem-solving suggestions. We've also specified ways for youto document less-than-perfect performance, so we canrespond promptly and equitably, and you can get onwith your work.But by all means, contact us if you need additionaladvice. We have experts on hand to see you throughwhatever challenges you face or concerns you havewith your Sappi job .

Sappi is proud of the reputation we've earned forhigh-quality coated printing papers. We want nothingto get in the way of your experience w ith Sappi.You have our promise.

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Call the Sappi North America Printer Help Linefor answers to print-related questions.

Former press professionals are available toanswer questions about your paper perfornnanceduring the print process. They can also offeradvice on press-related issues involving inks,coatings and bindery processes.

1.877.SappiHelp (1.877.727.7443)Visitwww.sappi.com/Knowledge_bankfor access to the Sappi Tech Tipstroubleshooting guides.

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Immediate NotificationAs soon as a problem is judged to be paperrelated, the printer or converter should immediately notify the Sappi merchant who provided itor the local Sappi sales representative.Documentation and EvidenceFor all claims, the following documentationis required:> Sappi invoice number or Sappi

order number> Product label from the job in question> Com pleted Sappi or MerchantComplaint Report> Detailed desc ription of the problem> Sufficient evidence of the proble m,

as stated in the guidelines in this booklet

All charges should be clearly stated at costand detailed with regard to hourly rates forpress tim e.All claims are processed through the Sappipaper merchant.

ConditioningSappi paper is shipped in moisture-resistantpackaging to ensure dimensional stability andflatness upon delivery. After the packaging isopened, however, Sappi cannot be heldresponsible for printing problems due tomoisture imbalance or other environmentalconditions in the printer's shop.Precautionary Measures> Allow time for paper to acclimate

to pressroom environment beforeopening packaging

> Avo id cutting paper for press any soonerthan necessary> Rewrap cut paper as soon as possible> Open no more paper than necessary during

makeready and prior to approval> Remove the top and bottom sheets, which

may have been damaged during packaging,handling or transit

> Save 16 consecutively numbered printedand unprinted sheets w ith DEFECT CIRCLED.

> Flip 50 sheets prior to production run toassess side-to-side print consistency

> Cover press loads between passes to helpmaintain sheet integrity and stability

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Recommended Pressroom EnvironmentIt is important to monitor relative humidity and temperature. The ambienttemperature and humidity of the pressroom may be too high or too low,which may affect ink tack and drying, and cause static, tight or wavyedges, paper picking and delamination.Ideal pressroom climate control is 45% (+/-5%) Rh at 72(+/-5) Ffor North America, 52% (+/-5%) at 21 C in Europe.Allow paper to acclimate to pressroom temperature.> Paper will acclimate in skids, cartons and reams.

Do not open until going to press.> Paper acclimation time is relative to environmental extremes .

The industry accepted best practice is 24-48 hours, or even longerdepending on temperature differential and volume of paper.

> Properly cond itioned paper runs with a broader operating windowon press. Cold paper in a warm pressroom is prone to condensation,which can lead to wavy edges. Cold paper also has greatersusceptibility to picking, delamination and slow ink dry.

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The following section outlines the troubleshootingprocess for some of the more common issues that papersuppliers are often asked to address. If these problemscannot be overcome on press, we have also includedguidelines for submitting the necessary evidence to filea claim when paper is suspect.We encourage the submission of additional informationand/or evidence that may be available so that ourtechnical experts can most effectively understand theproblem, then identify and eliminate the source ofthe defect.

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Required DocumentationThe fol lowing documentat ion is required for al l c laims:> Sap pi invoice num ber or Sap pi order num ber> Produ ct label f rom the job in que st ion> Com pleted Sappi or Merchant Com pla int Repor t> Detai led desc r ipt ion of the problem> Suff ic ient eviden ce of the problemAll claims are processed through the Sappipaper merchant.

Simple Steps for ClearCommunication of Problems> Identify all sam ples clearly> Circle any defe cts> Identify press mo del, press size, num ber of

passes and ink color sequence> Provide pressroom hum idity and temperature> Send samples FLAT when appropriate

(e.g., misregistrat ion, wavy edges, corruga tion or r idges)> Send com petit ive samp les if referenced

(both printed and unprinted)> Use transparent pull tape to take contam inant samp les

from a blanket, a plate, or the side of a skid or roll> Put tape on clear acetate; DO NOT FOLD TAPE

OR ATTACH TO PAPER SAMPLE S

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Hickeys occur when contaminating particles adhere tothe plate or blanket, causing either a doughnut effect(small solid printed island surrounded by a white halo) oran unprinted void surrounded by printing.

Suggestions: Dip out ink fountain; drop fountain bladeand clean; inspect roller condition; add fresh ink fromnew can or change inks.For further information on hichmrj'^ . .-; - t? C-a,4 : *V,> 'K .or vi?.!"-www.sappi.ccn* K .:

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Documenting the Problem

#4561Provide Sappi invoice number or Sappi order number.

Complete the Merchant or Sappi Complaint Report .

Provide roll or skid/carton/ream label.

Send 16 consecutively numbered printed and unphnted sheets or 10 feet(3 m) of unphnted web lead with DEFECT CIRCLED. Write run number fromskid, carton or ream on sample or roll number from roll label on sample.

Remove part icles of contamination from blanket or plate usingtransparent tape. Put tape on clear acetate or f i lm. DO NOT FOLDTAPE or attach to paper. DO identify the unit on a mult icolor press.

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If ink is too tacky, or if the coating is defective, bits ofcoating/fiber are pulled from the paper's surface. Thismaterial adheres to the blanket and leaves a color voidor surface crater in the printed sheet where the pick-outfirst occurred. Subsequent sheets show partial filling, ormay continue to show absence of one or more colors.Suggestions: Clean blankets, change contaminated ink,reduce impression cylinder squeeze or reduce ink tack.Try a different production run of paper.

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Provide Sappi invoice number or Sappi order number.

Complete the Merchant or Sappi Complaint Report.


Send 16 consecutively numbered printed and unprinted sheets or 10 feet(3 m) of unprinted web lead with DEFECT CIRCLED. Write run number fromskid, carton or ream on sample or roll number from roll label on sample.

Remove particles of contamination from blanket or plateusing transparent tape. Put tape on clear acetate or film.DO NOT FOLD TAPE or attach to paper. DO identify theunit on a multicolor press.

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Piling/Tail-edge pick occurs when ink builds up on theblanket until it eventually lifts off a portion of the imageor pulls the fibers or coating from the sheet. This can becaused by defective paper coating, wrong ink consistency, inadequate film of fountain solution, improperfountain solution mix, excessive impression cylindersqueeze or blanket wash that renders the blanket sticky.Suggestions: Try a lower tack or lower set rate of ink,and/or increase fountain solution to plate. If abovesuggestions do not work, replace the blanket or try adifferent production run of paper.

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II Provide roll or skid/carton/ream label.


Remove particles of contamination from blanket or plate usingtransparent tape. Put tape on clear acetate or film. DO NOT FOLDTAPE or attach to paper. DO identify the unit on a multicolor press.

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Loose dust particles on the paper surface adhere to theblanket, take on ink and print as dark specks, or show upas voids in print.Dust deposits can occur during sheeting ortrimming operations.Suggestions: Predust on impression with a dry, blankunit; inspect all four sides of paper for cut quality; wipeedges with a glycerin or tack cloth; trim paper on all foursides or replace with a different production run of paper.


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Send 16 consecutively numbered printed and unphnted sheets or 10 feet(3 m) of unphnted web lead with DEFECT CIRCLED. Write run number fromskid, carton or ream on sample or roll number from roll label on sample.

Remove particles of contamination from blanket or plate usingtransparent tape. Put tape on clear acetate or f i lm. DO NOT FOLDTAPE or attach to paper. DO identify the unit on a multicolor press.

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Sometimes a foreign object or a paper defect canactually smash, or render useless, a blanket or a plate.The only remedy is to clear away whatever hascaused the damage, spot-check the remaining paperand replace the blanket or plate.

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Provide Sappi invoice number or Sappi order number.#4561

\*&L Complete the Merchant or Sappi Complaint Report.


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Send 16 consecutively numbered printed and unprinted sheets or 10 feet(3 m) of unprinted web lead with DEFECT CIRCLED. Write run number fromskid, carton or ream on sample or roll number from roll label on sample.Also include paper or material causing the smash/damage.All blankets and plates should be held for Sappi inspection.

Identify the printing unit or units involved.

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Scratches or blade streaks are generally of shortduration and are usually isolated to a small portion ofthe paper order.They sometimes occur during the coating operation in thepaper mill when a particle of grit or other contaminantbecomes lodged between the coating blade and thepaper. This cu ts a groove into the paper's coating in thegrain direction. Very light scratches can be caused bysheeting equipment.Suggestions: Isolate and replace affected paper.

D a k o t a F o o d s p r o d u c e s

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J I Provide roll or skid/carton/ream label.


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Delamination occurs when the paper itself pulls apartduring printing. The surface of the paper may appearbubb led or lifted. There can be numerous causes ofthis problem: high-tack inks, partially dried ink on therollers/blanket or high impression squeeze.Delamination is not to be confused with blistering, whichoccurs almost exclusively in the dryer unit of a web press.Suggestions: Reduce ink tack on the rolls, reduceimpression squeeze or try a different production runof paper.

ther informe lamina> Sappi Tech Tips ank.

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Printing dots do not precisely align, causing a blurredimage or color variance; register marks are out of sync.This can be the result of gripper slip, loose blankets,high ink tacks , m isalignment on the feed table,bowed/scalloped/wavy sheet edges, quality differencesbetween the consecutive sheets or off-square paper.Suggestions: Adjust and clean grippers, torque blanketsto spec, lower ink tack, readjust feed table, reduceimpression squeeze, check sheet for wavy/tight edgesand relief-cut blanket packing outside image area. Trya different production run of paper.


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This occurs when ink transfers to the back side of the nextsheet, sometimes causing the sheets to stick together.Offsetting can be due to insufficient spray powder, deliverypile that is stacked too high, excessive ink film, slow dryingink or paper, or a combination of water/ink balance andhumidity conditions.Suggestions: Increase or change spray powder, decreaseheight of the delivery stack, run a stronger pigmented inkwith less ink film or adjust ink/water balance.

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Send 16 consecutively numbered printed and unprintedsheets with DEFECT CIRCLED. Write run number from skid,carton or ream on sample.

Provide temperature and relative humidity of the pressroom.

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Mottle occurs when the ink lies unevenly on the sheet,especially in an area of uniform color, or cyan/magenta inktrap, like a blue sky.Suggestions: Pull single prints to identify problem printingunit(s). For cyan/magenta mottle, reverse ink sequence andtack accordingly. Run tack-graded inks with the highesttack down first. Trap heavier coverage down last and putsolid colors in latter-down units. Increase press speed, flipsheets or try a different production run of paper.For furthewww.sapF idge_bank.

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#456(Provide Sappi invoice number or Sappi order number.



Send 16 consecutively numbered printed and unprinted sheets or 10 feet (3 m)of unprinted web lead with DEFECT CIRCLED. Write run number from skid,carton or ream on sam ple or roll number from roll label on sample. Send singleblack, 2-color (black-cyan), 3-color (black-cyan-magenta) and 4-color prints.

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Blistering, the occurrence of small bubble-like formations onboth sides of the web paper, can occur when trappedmoisture vaporizes as the printed paper is passing throughthe dryer on a web press. Causes vary, but are often tracedto excessive dryer temperature, slow press speed and/orhigh-flash/high-solvent inks, paper moisture or form design.Heavyweight coated paper is more susceptible to blistering.Suggestions: Increase press speed and/or decreaseoven temperature, reduce ink/varnish film or use a lowerflash ink so oven temperature can be reduced. Isolateproblem rolls by machine reel or roll position. Try a differentproduction run of paper.For further information on Consideratic g Web Cover refer to Sappi Tech Tip

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Provide roll label.

Send 16 consecutively numbered printed signatures and10 feet (3 m) of unprinted web lead with DEFECT CIRCLED.Write roll number from roll label on sample.

Record dryer temperatures of the separate sections,web exit temperature and web spee d.

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A roll with a soft or loosely wound edge or center thatcreates non-uniform tension across the web. Hardnessprofiles across the roll vary from soft to hard.Suggestions: Increase web tension, flop suspect rollsto move the slack edge to the more forgiving side of thepress or isolate suspect rolls by roll position by measuringdelta-hardness with a Schmidt Hammer. Try running rollsby position number in consecutive order to reduce roll-to-roll variability.

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Provide roll label.

Send 16 consecutively numbered printed signatures and10 feet (3 m) of unprinted web lead with DEFECT CIRCLED.Write roll number from roll label on sample.

Record dryer temperatures of the separate sections,web exit temperature and w eb speed .

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Provide roll label.

* Send 16 consecutively numbered printed signatures and10 feet (3 m) of unprinted web lead with DEFECT CIRCLED.Write roll number from roll label on sample.n I f possible, submit a printout of the Schmidt Hammerdelta-hardness readings measured 3 inches (8 cm) apartacross the roll, beginning 3 inches (8 cm) in from each edg e.If Schmidt Hammer readings are not an optio n, provide picturesof either web edge f lutter under tension , non-uniform tensionacross web, pencil penetration into roll edge or finger pressurecompressing roll edge.

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Wavy paper can cause problems with wrinkles, misregistration, dot slur or the aesthetics of the final printedsheet. This condition can be aggravated if the paper isexposed to extreme temperature or humidity changes.

Suggestions: Keep the paper wrapped until time ofprinting and cover loads between passes on press.Maintain proper temperature and humidity in pressroom.Try a different production run of paper.

appi Tech

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#456(Provide Sappi invoice number or Sappi order number.



Send 16 consecutively numbered printed and unprintedsheets with DEFECT CIRCLED. Write run num ber fromskid, carton or ream on sample and ship samples f lat.

Provide temperature and relat ive humidity of the pressroom.

If samples appear to be wavy, provide low-angle, edge-onpicture of a load of unprinted sheets.

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When in doubt, provide as much evidence as possible.#4561

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Complete the Merchant or Sappi Complaint Report .


Send 16 consecut ive pr inted and unprinted sheetsand/or 10 feet (3m) of unprinted web lead with DEFECTCIRCLED. Write run number from skid, carton or reamon sample or roll number from roll label on sample.Remove part icles of contamination from blanket or plateusing transparent tape. Put tape on clear acetate or f i lm.DO NOT FOLD TAPE or attach to paper. DO identify theunit on a mult icolor press.

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Printer Help Line1.877.SappiHelpDescript ion of ProblemO Pick ing /Contaminat ionO Scratches /B lade St reaks /Sur face De fectsO PilingO DelaminationO Misregistrat ion/SlurO Wavy PaperO Other

O Mot t leO Bl isteringO Baggy RollsO Wr ink les

Explanat ion of Lost Press Time

Resolut ion

Costs Associated With ClaimType of Cost:Lost Press TimeMakereadiesUnprinted Paper to ReturnBlanketsPlatesPrinted SpoilageOther

Quantity:

Complaint ReportDate Submi t ted :

Merchan t In fo rmat ionMerchantContact/Sales RepPhone No.Address/Location

Date o f Occurrence: Submi t ted by:

Printer Informat ionPrinterPrinter ContactPhone No.Address/Location

Merc hant P.O. No. i Sappi Order No. i Sappi Invoice No. Job Name/No. i Printer P.O. No

Prob lem D iscoveredO At Printer O BinderyO At End User O Other:O First PassO Subsequent PassesO After PrintingPaper Detai ls

Grade

Paper Shipped:Direct Merchant Stock

O O

Paper Cu t byO Mill O Other:O MerchantO PrinterWas paper wrapped until printed?

O Yes O No

Act ion TakenO Job CompletedO Job PulledO Paper ReplacedO Paper Replacement Grade:

Sheet Size/Roll WidthBasis WeightOther Grade for ComparisonGrain

Package/Skid/Carton/Roll No.Quantity/No. SheetsUnprintedPrinted

O oPackages Cartons OSkids oRolls

Plant Condit ionsPressroom: O Climate ControlledAmbient Temperature/RhStorage: O Climate ControlledAmbient Temperature/RhWeather: O Dry O Humid O Extended Dry/Wet WeatherHow long did paper acclimate?

Print ing Detai lsO Conventional O Digital O Dry Offset O UVO Other;Press Manufacturer/M odel Size

(2) (3) (4)olor Side 1(1)Sequence: S j d e 2 ( 1 )

Press Speed: IPHInk TackFountain Solutions: pHOven Type/Length

(2)

FPM

(3) (4)No. of Passes

Ink AdditivesConductivity

No. of Units(5) (6)(5) (6)

Type of Blanket

Web Temperature

Unit Cost:

No. of Colors(7) (8)(7) (8)

Printed: O Work/TurnO Grain Long O TumbleO Grain Short O Sheetwise

Total Cost:

All submitted claims must include a label fromthe produc t and suff ic ien t ev idence necessaryto document, wi th de fec t c lea r ly c i rc led .Please sign and submit to yourdistributing merchant for processing:

Signature Total Amount of Claim


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Provide temperature and relative humidity ofthe pressroom.

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I f samples appear to be wavy, provide low-angle,edge-on picture of a load of unprinted sheets.

All blankets and plates should be held forSappi inspection.

Identify the printing unit or units involved.

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PRODUCTION NOTESFRONT COVEROpus Gloss Cover 100lb/270gsm4-color process, black, spot gloss varnish.

BACK COVEROpus Gloss Cover 100lb/270gsm4-color process, black, spot gloss varnish.INSIDE FRONT COVEROpus Gloss Cover 100lb/270gsm4-color process, spot gloss varnish.INSIDE BACK COVEROpus Gloss Cover 100lb/270gsm4-color p rocess, black, spot gloss varnish.INSIDE PAGESOpus Dull Text 100lb/148gsm4-color process, m atch blue, spot gloss varnish.

i 2005 Sappi Fine Paper No rth America. All r ights reserved.


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Sappi Fine Paper Europe-Head OfficeSappi Europe SA154 Chaussee de la HulpeB-1170 BrusselsBelgiumTel +32 (0)2 676 9700Fax +32 (0)2 676 9660

Sappi Fine Paper North America-Head Office28th floor225 Franklin StreetBoston MA 02110United States of AmericaTel+1 (617)423 5400Fax+1 (617)423 5494

Sappi Fine Paper South Africa-Head Office48 Ameshoff Street2001 BraamfonteinJohannesburgSouth AfricaTel+27 (0)11 40 7 8111Fax +27 (0)11 339 8022Sappi Trading-Head Office41 st Floor, AlA Tower183 Electric RoadNorth PointHong KongTel +852 (0)2877 3229Fax +852 (0)2877 4699Website address:www.sappi .com/Knowledge_bank
http://www.sappi.com/Knowledge_bankhttp://www.sappi.com/Knowledge_bank

sappi technical series press troubleshooting

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