Printer's Complaint checklist, helping your pressroom solve pressroom problems with paper and ink.

Blanket Smashes I Blistering I Contamination I Calendar Cuts I Cracking or Tearing at the Fold I Delamination I Ink Lay I Misregister I Moisture Problems I Picking I Picking Problems I Slime Holes I Splice Breaks I Comments on pH and conductivity I Printing Terms

Return Home I Printing Terms

Printer's Complaint Checklist:

Sampling Procedures

It is the merchant’s responsibility, with the help of the printer, to obtain order numbers and physical evidence to accurately demonstrate the nature of the printing problem. Here are recommended procedures and the symbol codes, which will be used throughout this web site for you to use as a guide:

	Information: All information required by the mill should be filled in on the complaint form. Gather and record all mill order numbers. Identify press type, press size, printing sequence, blankets used, dampening system type and pressroom conditions.
	Ink from the Can and Rollers: Ink samples from the can and obtain fountain will help determine the condition of the ink as it was received into the pressroom, and also after it has been on press. A sample of each of at least for else's should be placed in an air tight, in a non-porous container and sealed with vinyl or plastic tape.
	Printed Sheets with Original: Room temperature is imperative to obtain the press sheet or Web signature, which contains not original defect being described. When obtaining printed sheets, be sure to collect at least 12 consecutive sheets, including several sheets immediately before and after the original. Clearly identify that defect by circling it and staple this sheets together.
	Unprinted White Paper:Web and sheet-fed Samples of the unprinted paper, which have not been through the press, should be obtained so a complete analysis can be done at the mill. Sheet-that unprinted and printed sheets should be wrapped and shipped flat whenever possible. Web paper can be rolled and placed in a mailing tube.
	Tape-Pulls: When the press becomes contaminated with material that is causing print interference, it is necessary to retrieve this material for further analysis. A recommended material is clear adhere laminating sheets, which allow the sample to be pulled from the press and rejoined with a backing sheet which can be then identified as to where the tape-pull was taken.
	Fountain Solution: If it is necessary to obtain a sample of the water from the presses water system, be sure to use an airtight plastic container. Label the bottle as to which unit it came from and include all information regarding the mixture.
	Blanket Smashes: Send the damaged blanket along with the tape-pull of the material(s) that caused the smash. The certain to roll the blanket and place it in a mailing tube.
	Photographic Documentation: Occasionally it would be helpful to take a picture of certain paper and/or press conditions in the pressroom, such as moisture related problems or excessive piling. If the photo will supplement the other physical evidence, include it with the information going to the mill.
	Packaging: Sheet-fed unprinted and printed sheets should be wrapped and shipped flat whenever possible. Web paper can be rolled and placed in a mailing tube. Be sure the items are properly labeled in accordance with postal and other applicable transportation regulations.

Proper packaging procedures apply to all materials being returned for evaluation.

Blanket Smashes
Back to top Description: A compressed or smashed area(s) on a blanket due to excessive pressure against the blanket's surface in the printing nip. Causes: 1. Scuffs-a roll-up of paper, usually originating at the edge of a sheet. 2. Scraps-paper trimmings, folded sheets, labels, packaging materials etc. 3. Splices in cartons or skids. 4. Folded edges. Possible Solution: Replace blanket Precautions: 1. On sheet-fed jobs: a. The top and bottom sheets in a carton should be removed or examined carefully before printing because these sheets are the most susceptible to damage during handling, i.e., scuffs, folded edges, tears, etc. This is an accepted trade practice. b. When loading the press, examine the sides of the lift for any signs of a problem. 2. web Jobs: Roll labels indicate the number of splices in a roll. The location of a splice it is marked on one side of all rolls.
Documentation:

Blanket Smashes

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Description:

A compressed or smashed area(s) on a blanket due to excessive pressure against the blanket's surface in the printing nip.

Causes: 1. Scuffs-a roll-up of paper, usually originating at the edge of a sheet. 2. Scraps-paper trimmings, folded sheets, labels, packaging materials etc. 3. Splices in cartons or skids. 4. Folded edges. Possible Solution:

Replace blanket
Precautions:
1. On sheet-fed jobs:
a. The top and bottom sheets in a carton should be removed or examined carefully before printing because these sheets are the most susceptible to damage during handling, i.e., scuffs, folded edges, tears, etc. This is an accepted trade practice.
b. When loading the press, examine the sides of the lift for any signs of a problem.
2. web Jobs: Roll labels indicate the number of splices in a roll. The location of a splice it is marked on one side of all rolls.

Documentation:

Blistering
Back to top Description: A blister is a bubble-like formation that occurs on a coated sheet during drying in a web oven. Causes: The blister(s) is caused by the "explosion" which occurs is when the moisture within the sheet vaporizes and cannot escape through the paper's coating layer and ink film. Precautions: When blistering is experienced on press the following suggestions may help determine the cause or minimize a problem: 1. Determine the paper's surface temperature (PST) as the web exits the oven, and low where it, if possible, by: a. Decreasing the web speed and oven temperature proportionately. b. Increasing the web speed. c. Changing to inks that have higher tinctoral strength, which would require less heat. 2. If the blisters are confined to one area of the form, turn the roll around to determine if the blisters follow the paper, or remain with the press. Hot spots in the oven can be detected by intentionally scorching the sheet. 3. Check machine roll and roll positions for comparisons, if possible. Isolating the problem rolls may enable the printer to complete the job.
Documentation:

Blistering

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Description: A blister is a bubble-like formation that occurs on a coated sheet during drying in a web oven.
Causes: The blister(s) is caused by the "explosion" which occurs is when the moisture within the sheet vaporizes and cannot escape through the paper's coating layer and ink film.
Precautions: When blistering is experienced on press the following suggestions may help determine the cause or minimize a problem: 1. Determine the paper's surface temperature (PST) as the web exits the oven, and low where it, if possible, by: a. Decreasing the web speed and oven temperature proportionately. b. Increasing the web speed. c. Changing to inks that have higher tinctoral strength, which would require less heat. 2. If the blisters are confined to one area of the form, turn the roll around to determine if the blisters follow the paper, or remain with the press. Hot spots in the oven can be detected by intentionally scorching the sheet. 3. Check machine roll and roll positions for comparisons, if possible. Isolating the problem rolls may enable the printer to complete the job.

Documentation:

Contamination
Back to top Description: Print interference which results in non-print areas or specks in printing. Causes: 1. Ink Hickeys - Are caused by material, which is carried by the ink, and are not particles, which originate from the paper. Possible sources of the ink hickeys are pieces of ink skin, uncooked resin in the ink or roller fragments from a dry or deteriorating rubber ink roller. 2. Pick-outs and Coating Lumps- Are agglomerates of fiber coating material that are poorly bound into the paper coating or adhered to the paper's surface. 3. Coating Pick- Also referred to as" Pepper Picking," is the result of the lack of the ink exceeding the cohesive binding strength of the coating materials. 4. Wood Vessel Segments- Are fibers which, because of their composition, are difficult to remove during pulping procedures, and tend to be poorly bound into a coated paper. 5. Occasionally the print can be disrupted by fibers, which have contaminated the system. In general, fibers are water receptive and reject ink. These fibrous materials will adhere to the blanket or plate and except water but will not take on any ink, and will therefore cause in the print in the form of its own shape. 6. Pits May be described as indentations or wells in the surface of the paper or plate. Pits cause specks in print because the ink for rollers cannot apply ink down into the pits in the plate; and the blanket cannot apply ink down into the pits on the paper's surface. 7. Loose surface dust on paper is a major cause of specks in printing. When the loose dust sets on the paper's surface, it prevents the ink from reaching the sheet and sticks to the blanket. 8. In both sheet-fed and web printing the interaction of ink, fountain solution and paper must be kept in proper balance or a printing defect will occur which is commonly referred to as water interference. Water interference manifests itself as white specks in print, and tend to originate from three different sources: *Ink*-water emulsification rates *Paper*-receptivity to water *Fountain Solution*-Wettability 9. Specks in printing caused by anti-offset spray will occur in the sheet-fed printing and are normally a result of running too much spray. The excess spray will interfere with subsequently applied ink. 10) Piling is a build-up of ink and/or paper the team real on the blanket during printing. There are three common types of piling: Image area paper piling Image area Ink piling Non--image area piling
Documentation:

Contamination

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Description: Print interference which results in non-print areas or specks in printing.
Causes:
1. Ink Hickeys - Are caused by material, which is carried by the ink, and are not particles, which originate from the paper. Possible sources of the ink hickeys are pieces of ink skin, uncooked resin in the ink or roller fragments from a dry or deteriorating rubber ink roller.
2. Pick-outs and Coating Lumps- Are agglomerates of fiber coating material that are poorly bound into the paper coating or adhered to the paper's surface.
3. Coating Pick- Also referred to as" Pepper Picking," is the result of the lack of the ink exceeding the cohesive binding strength of the coating materials.
4. Wood Vessel Segments- Are fibers which, because of their composition, are difficult to remove during pulping procedures, and tend to be poorly bound into a coated paper.
5. Occasionally the print can be disrupted by fibers, which have contaminated the system. In general, fibers are water receptive and reject ink. These fibrous materials will adhere to the blanket or plate and except water but will not take on any ink, and will therefore cause in the print in the form of its own shape.
6. Pits May be described as indentations or wells in the surface of the paper or plate. Pits cause specks in print because the ink for rollers cannot apply ink down into the pits in the plate; and the blanket cannot apply ink down into the pits on the paper's surface.
7. Loose surface dust on paper is a major cause of specks in printing. When the loose dust sets on the paper's surface, it prevents the ink from reaching the sheet and sticks to the blanket.
8. In both sheet-fed and web printing the interaction of ink, fountain solution and paper must be kept in proper balance or a printing defect will occur which is commonly referred to as water interference. Water interference manifests itself as white specks in print, and tend to originate from three different sources:
Ink-water emulsification rates

Paper-receptivity to water

Fountain Solution-Wettability
9. Specks in printing caused by anti-offset spray will occur in the sheet-fed printing and are normally a result of running too much spray. The excess spray will interfere with subsequently applied ink.
10) Piling is a build-up of ink and/or paper the team real on the blanket during printing. There are three common types of piling: Image area paper piling

Image area Ink piling

Non--image area piling

Documentation:

Calendar Cuts
Back to top Description: Calendar cuts are small cuts or slices in the paper. Causes: Wrinkles or creases in a roll of paper that is passing through a calendar stack under high-pressure may result in cuts along the wrinkle or creases. Possible Solution: The calendar cuts may be isolated to a particular roll. If this roll was sheeted into a palette or skid at the mill, then, the problem may only affect a small portion of a certain palette or skid. Every sheet may not have the problem. Calendar cuts usually have a recurring pattern example, every third, fourth, fifth sheet, depending on the number of roles sheeted into the palette or skid. Mill order numbers and put up numbers will help identify the extent of the problem. Nothing can be done about calendar cuts, except to sort them out or reject the paper.
Documentation:

Calendar Cuts

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Description: Calendar cuts are small cuts or slices in the paper.
Causes: Wrinkles or creases in a roll of paper that is passing through a calendar stack under high-pressure may result in cuts along the wrinkle or creases.
Possible Solution: The calendar cuts may be isolated to a particular roll. If this roll was sheeted into a palette or skid at the mill, then, the problem may only affect a small portion of a certain palette or skid. Every sheet may not have the problem. Calendar cuts usually have a recurring pattern example, every third, fourth, fifth sheet, depending on the number of roles sheeted into the palette or skid. Mill order numbers and put up numbers will help identify the extent of the problem. Nothing can be done about calendar cuts, except to sort them out or reject the paper.

Documentation:

Cracking or Tearing at the Fold
Back to top Description: 1. Cracking at the fold (CAF) occurs when the coating fractures as the sheet is folded and can be a problem in both sheet-fed offset and web offset printing. 2. Tearing at the fold (TAF) occurs when it printed and folded job falls apart to along a folded edge or around the staples after binding. TAF occurs most often in web offset printing. Causes: 1. CAF can be caused by: A. Attempting to fold heavyweight papers without scoring. B. Improper scoring. C. Low moisture conditions. D. Improper folder nip settings. 2. TAF can be caused by: a. Excessive heat in the web oven. b. Weak paper. c. Improper folder setting. d. In adequate to chill roller temperature. Precautions 1. Crack at the Fold It is recommended that papers 100 lb. and up in basis of weight is scored prior to folding. 2. Tear at a folded a. web exit temperatures should be run at the minimum necessary to dry the ink. b. Folding units should be set properly to place minimum squeeze, and the Tucker blade adjustment should be accurate so as not to shear the fold.
Documentation:

Cracking or Tearing at the Fold

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Description: 1. Cracking at the fold (CAF) occurs when the coating fractures as the sheet is folded and can be a problem in both sheet-fed offset and web offset printing. 2. Tearing at the fold (TAF) occurs when it printed and folded job falls apart to along a folded edge or around the staples after binding. TAF occurs most often in web offset printing.
Causes:

1. CAF can be caused by:

A. Attempting to fold heavyweight papers without scoring.
B. Improper scoring.
C. Low moisture conditions.
D. Improper folder nip settings.
2. TAF can be caused by:
a. Excessive heat in the web oven.
b. Weak paper.
c. Improper folder setting.
d. In adequate to chill roller temperature.
Precautions

1. Crack at the Fold

It is recommended that papers 100 lb. and up in basis of weight is scored prior to folding.
2. Tear at a folded
a. web exit temperatures should be run at the minimum necessary to dry the ink.
b. Folding units should be set properly to place minimum squeeze, and the Tucker blade adjustment should be accurate so as not to shear the fold.

Documentation:

Delamination
Back to top Description: Paper peeling apart or separating from within. Note: Do not confuse delamination with blistering in web printing. Blisters all occur in the oven. Delamination occurs in the printing units. Causes: If the internal bond of the paper cannot withstand the tack, or printing forces, during printing, the sheet will separate or delaminate. Possible Solution: In general, the only viable solution is to reduce the tack of the ink being used. An alternative would be to run another lot of paper.
Documentation:

Delamination

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Description:

Paper peeling apart or separating from within. Note: Do not confuse delamination with blistering in web printing. Blisters all occur in the oven. Delamination occurs in the printing units.
Causes: If the internal bond of the paper cannot withstand the tack, or printing forces, during printing, the sheet will separate or delaminate.
Possible Solution: In general, the only viable solution is to reduce the tack of the ink being used. An alternative would be to run another lot of paper.

Documentation:

Ink Lay (Mottle)
Back to top Description: Mottle is a phrase used to describe non-uniform ink lay or when the printed reproduction has a pattern, which is not present in the original artwork. Causes: Mottle can be due to several ink-paper-press or "system" problems. Among these are: 1. Back trap mottle 2. Wet ink trap mottle 3. Paper mottle 4. Water interference mottle Possible Solution: If the printer is experiencing and ink lay problem the following items should be checked: 1. Inks should be tack graded to print with the highest tack first 2. Quick release blankets may help minimize a problem 3. The fountain solution should be run with minimum concentrate to run clean any should be monitored by measuring conductivity 4. Progress of the prints should be pulled to determine which printing units(s) create the problem 5. All problem-shooting prints should be done at the production speed 6. At least 50 sheets should be turned over and printed on the opposite side to determine if the ink lay changes. 7. Another lot of paper could be run as a comparison
Documentation:

Ink Lay (Mottle)

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Description: Mottle is a phrase used to describe non-uniform ink lay or when the printed reproduction has a pattern, which is not present in the original artwork.
Causes: Mottle can be due to several ink-paper-press or "system" problems. Among these are:
1. Back trap mottle
2. Wet ink trap mottle
3. Paper mottle
4. Water interference mottle
Possible Solution: If the printer is experiencing and ink lay problem the following items should be checked:
1. Inks should be tack graded to print with the highest tack first
2. Quick release blankets may help minimize a problem
3. The fountain solution should be run with minimum concentrate to run clean any should be monitored by measuring conductivity
4. Progress of the prints should be pulled to determine which printing units(s) create the problem
5. All problem-shooting prints should be done at the production speed
6. At least 50 sheets should be turned over and printed on the opposite side to determine if the ink lay changes.
7. Another lot of paper could be run as a comparison

Documentation:

Misregister
Back to top Description: Failure of the printed images to align in multicolor printing Causes: Misregister may be caused by a number of factors: 1. A moisture imbalance in the stock 2. Inaccurate trimming 3. Paper slippage in the grippers 4. Loose blanket or plate 5. Improper winding of web roll 6. Improper stripping Possible Solutions: 1. Care should be taken to allow skid and roll to acclimate to pressroom conditions while wrapped (sheets and web) 2. Retrim the paper if possible so the grippers and side guide have a stable edge 3. Try a roll from a different reel position (web)
Documentation:

Misregister

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Description: Failure of the printed images to align in multicolor printing
Causes: Misregister may be caused by a number of factors:
1. A moisture imbalance in the stock
2. Inaccurate trimming
3. Paper slippage in the grippers
4. Loose blanket or plate
5. Improper winding of web roll
6. Improper stripping
Possible Solutions:
1. Care should be taken to allow skid and roll to acclimate to pressroom conditions while wrapped (sheets and web)
2. Retrim the paper if possible so the grippers and side guide have a stable edge
3. Try a roll from a different reel position (web)

Documentation:

Moisture Problems
Back to top Description: Moisture problems or current due to differentials in the relative humidity between the paper and its environment Causes: Paper fibers are hydrophilic, or water loving, and react rapidly to changes in moisture conditions of their environment. Wrinkling of the stock, which has absorbed moisture, may develop a wrinkling problem two thirds of the way back from the gripper edge and continue to the back edge of the sheet. Tight edged paper, or paper which has given off moisture, may create a wrinkling problem in the center of the sheet. Possible Solutions: 1. When a moisture problem is encountered, try turning the lift to use the opposite edge to the grippers. This may eliminate the wrinkling problem; however, this is usually more successful when encountering wavy edge-type wrinkling problems. 2. While keeping the stock wrapped, allow approximately one day for every 10% incremental difference between the RH of the paper and pressroom. This will stabilize the paper. 3. Abnormal conditions in this touring of paper may result in a moisture related paper problem. Once a skid or carton is opened and the stock is exposed to the atmosphere, it is standard practice to cover that paper to protect it from climate changes. The presence of moisture in the offset printing process, together with the stock's exposure to a different atmosphere, may cause flat, acceptable stock to react.
Documenation:

Moisture Problems

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Description: Moisture problems or current due to differentials in the relative humidity between the paper and its environment
Causes: Paper fibers are hydrophilic, or water loving, and react rapidly to changes in moisture conditions of their environment. Wrinkling of the stock, which has absorbed moisture, may develop a wrinkling problem two thirds of the way back from the gripper edge and continue to the back edge of the sheet.
Tight edged paper, or paper which has given off moisture, may create a wrinkling problem in the center of the sheet.
Possible Solutions:
1. When a moisture problem is encountered, try turning the lift to use the opposite edge to the grippers. This may eliminate the wrinkling problem; however, this is usually more successful when encountering wavy edge-type wrinkling problems.
2. While keeping the stock wrapped, allow approximately one day for every 10% incremental difference between the RH of the paper and pressroom. This will stabilize the paper.
3. Abnormal conditions in this touring of paper may result in a moisture related paper problem. Once a skid or carton is opened and the stock is exposed to the atmosphere, it is standard practice to cover that paper to protect it from climate changes. The presence of moisture in the offset printing process, together with the stock's exposure to a different atmosphere, may cause flat, acceptable stock to react.

Documenation:

Picking
Back to top Description: Picking (coating pick, Pepper picking) is the result of the tack of the ink exceeding the cohesive or binding strength of the sheet. Picking is not lifting coating and/or paper fibers from the sheet, and can produce non-print areas of various shapes and sizes. An original pickout has depth and a creater-like appearance. The result of this pickout on subsequently printed sheets is opened voids, which show the surface of the sheet without depth, or merely an unprinted speck in the same size and shape of the original. Examination under a printer's loupe, along with a low angle light, will enable you to determine which sheet contains the original pickout. Causes: 1. Insufficient to paper surface strength 2. Excessive ink tack or tack-build during printing Possible Solutions 1. Picking can be more severe during a make-ready when the ink and press remain stationary for extended time intervals. This can be particularly true when a light coverage form is being run. Be certain enough paper has been run through the press for a system to be stable before attempting to address a problem. 2. Decrease impression in squeeze to at minimum 3. Before reducing the tack of the ink, have the press person pull progressive prints, beginning with the first unit, to determine where the picking is occurring. Once you have determine which ink(s) is causing the picking, then adjustments to the ink can be made. For example, if the first down black is causing the pick, and a print of the black alone shows the picking, then reducing the tack of the black should improve the problem. However, if the black ink alone does not cause picking, but it begins to pick as the additional inks are applied, then a more appropriate adjustment would be to reduce the setting rate, or stabilize the ink so that the build-up of tack through the press is slowed. 4. There are various blankets available in the market. A quick release blanket could be recommended for a printer with chronic problems.

Picking

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Description: Picking (coating pick, Pepper picking) is the result of the tack of the ink exceeding the cohesive or binding strength of the sheet. Picking is not lifting coating and/or paper fibers from the sheet, and can produce non-print areas of various shapes and sizes.
An original pickout has depth and a creater-like appearance. The result of this pickout on subsequently printed sheets is opened voids, which show the surface of the sheet without depth, or merely an unprinted speck in the same size and shape of the original.
Examination under a printer's loupe, along with a low angle light, will enable you to determine which sheet contains the original pickout.
Causes:
1. Insufficient to paper surface strength
2. Excessive ink tack or tack-build during printing
Possible Solutions
1. Picking can be more severe during a make-ready when the ink and press remain stationary for extended time intervals. This can be particularly true when a light coverage form is being run. Be certain enough paper has been run through the press for a system to be stable before attempting to address a problem.
2. Decrease impression in squeeze to at minimum
3. Before reducing the tack of the ink, have the press person pull progressive prints, beginning with the first unit, to determine where the picking is occurring. Once you have determine which ink(s) is causing the picking, then adjustments to the ink can be made.
For example, if the first down black is causing the pick, and a print of the black alone shows the picking, then reducing the tack of the black should improve the problem. However, if the black ink alone does not cause picking, but it begins to pick as the additional inks are applied, then a more appropriate adjustment would be to reduce the setting rate, or stabilize the ink so that the build-up of tack through the press is slowed.
4. There are various blankets available in the market. A quick release blanket could be recommended for a printer with chronic problems.

Picking Problems
Back to top Setting and Drying Description: 1. Setting: Ink setting time is the amount of time required for an ink to gel or set-up to the point where the sheet can be re-worked through the press. 2. Drying: The process of ink drying involves a chemical reaction that may require 24 to 48 hours to come to completion. Causes: It is important to determine if the problem is one of setting or drying. If the problem is setting, it could be due to: 1. The setting speed or formulation of not ink. 2. A paper, which has slow ink setting characteristics, may require small lifts, additional spray, or longer turnaround time. 3. An improper mixture of fountain solution concentrate or additives can change the emulsification characteristics of ink and/or interfere chemically with the setting and drying function of the ink. 4. Inadequate amount of offset spray. If the problem is drying, it could be due to: 1. The formulation of the ink 2. The improper mixture of the fountain solution. Possible Solutions: Normally ink setting and drying problems are recognized after a job has been printed on at least one side, which makes and analysis of the printing conditions at that time difficult. If the job is a work-and-turn form, probably minimum time has passed since the first side was printed. Therefore, the precautions to take would be: 1. Check the mixture of the fountain solution, and get a sample of the solution out of the circulating tank for further analysis. 2. Obtain samples of the ink from both the can and the fountain so an evaluation can be done. Note: Samples must be taken from the press at that time when the problem occurs. A note about web ink rub problems: During web printing the setting function is physical. The solvent in the heat-set ink is removed by the increase in temperature in the web's oven. The drying function in the web occurs in the chill roll section of the press, where the melted ink is cooled into a solidified state. When dry rub problems occur after web printing, the solutions above apply, along with the following: 1. Check the paper surface temperature at the oven's exit to assure that the solvents are being removed. 2. Check the chill wall temperatures to assure that the paper's surface temperature is being lowered to 50 to 70°F.

Picking Problems

Back to top Setting and Drying
Description:
1. Setting: Ink setting time is the amount of time required for an ink to gel or set-up to the point where the sheet can be re-worked through the press.
2. Drying: The process of ink drying involves a chemical reaction that may require 24 to 48 hours to come to completion.
Causes: It is important to determine if the problem is one of setting or drying. If the problem is setting, it could be due to:
1. The setting speed or formulation of not ink.
2. A paper, which has slow ink setting characteristics, may require small lifts, additional spray, or longer turnaround time.
3. An improper mixture of fountain solution concentrate or additives can change the emulsification characteristics of ink and/or interfere chemically with the setting and drying function of the ink.
4. Inadequate amount of offset spray.
If the problem is drying, it could be due to:
1. The formulation of the ink
2. The improper mixture of the fountain solution.
Possible Solutions: Normally ink setting and drying problems are recognized after a job has been printed on at least one side, which makes and analysis of the printing conditions at that time difficult. If the job is a work-and-turn form, probably minimum time has passed since the first side was printed. Therefore, the precautions to take would be:
1. Check the mixture of the fountain solution, and get a sample of the solution out of the circulating tank for further analysis.
2. Obtain samples of the ink from both the can and the fountain so an evaluation can be done.
Note: Samples must be taken from the press at that time when the problem occurs.
A note about web ink rub problems: During web printing the setting function is physical. The solvent in the heat-set ink is removed by the increase in temperature in the web's oven. The drying function in the web occurs in the chill roll section of the press, where the melted ink is cooled into a solidified state. When dry rub problems occur after web printing, the solutions above apply, along with the following:
1. Check the paper surface temperature at the oven's exit to assure that the solvents are being removed.
2. Check the chill wall temperatures to assure that the paper's surface temperature is being lowered to 50 to 70°F.

Slime Holes
Back to top Description: A slime hole appears as a hard and brittle contaminant around a hole in the base stock of the paper. Cause: Contamination in the fiber furnish during the papermaking process. Possible solutions: This problem is not an extensive one and normally will be confined to a limited amount of paper; example a few sheets or a small portion of a roll.

Splice Breaks
Back to top Description: In web printing, a mill-made splice causes the web to break as it progresses through the press. Cause: Check for: 1. Does the splice have a tail? 2. While his adhesive stock to the preceding the? 3. Where did the break occur? 4. Was the splice marked? Possible Solution: Web rolls-most roll labels indicate the number of splices in the roll. The location of the splice(s) is marked on one side of all rules. This enables the printer to take impression off and let a splice through the printing nips with minimal waste.

Splice Breaks

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Description: In web printing, a mill-made splice causes the web to break as it progresses through the press.
Cause: Check for:
1. Does the splice have a tail?
2. While his adhesive stock to the preceding the?
3. Where did the break occur?
4. Was the splice marked?
Possible Solution: Web rolls-most roll labels indicate the number of splices in the roll. The location of the splice(s) is marked on one side of all rules. This enables the printer to take impression off and let a splice through the printing nips with minimal waste.

Comments on pH and Conductivity
Back to top A number of fountain solution concentrates being used today are" combination" type products, which contain all the ingredients, needed for offset printing. All that must be added in the print shop is water and if used, is propylene alcohol. These concentrates, often referred to as" one-step" etches, can be a buffered solution. A simplified definition of" buffered" water mixture would be that you can add either acidic material or alkaline material to this mixture, and the pH value of the mixture will not change. Therefore, after a fountain solution has been mixed and placed in the press, the addition of more concentrate (acid) will not change the pH of the mixture. However, the acidity of the mixture has been increased. Using pH as the only measurement of the amount of concentrate in the fountain is no longer an accurate tool. An alternative measurement is conductivity. The amount of fountain solution concentrate in a fountain solution will determine the conductivity of the solution. Conduct DVD is generally measured and reported in micro mho/centimeter. The term umho (1/1,000,000 of mho) is used as the measurement unit of conductivity just like pounds are a unit of weight. Conduct DVD, or conductance, is the capability of a solution to carry (conduct) electricity through it. This is the opposite of resistance, which is the property of a solution to resist the flow of electricity.

Comments on pH and Conductivity

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A number of fountain solution concentrates being used today are" combination" type products, which contain all the ingredients, needed for offset printing.
All that must be added in the print shop is water and if used, is propylene alcohol.
These concentrates, often referred to as" one-step" etches, can be a buffered solution. A simplified definition of" buffered" water mixture would be that you can add either acidic material or alkaline material to this mixture, and the pH value of the mixture will not change.

Therefore, after a fountain solution has been mixed and placed in the press, the addition of more concentrate (acid) will not change the pH of the mixture. However, the acidity of the mixture has been increased.
Using pH as the only measurement of the amount of concentrate in the fountain is no longer an accurate tool.
An alternative measurement is conductivity. The amount of fountain solution concentrate in a fountain solution will determine the conductivity of the solution. Conduct DVD is generally measured and reported in micro mho/centimeter. The term umho (1/1,000,000 of mho) is used as the measurement unit of conductivity just like pounds are a unit of weight. Conduct DVD, or conductance, is the capability of a solution to carry (conduct) electricity through it. This is the opposite of resistance, which is the property of a solution to resist the flow of electricity.