The Offset Pressman

Troubleshooting Crooked Fold At Chopper / Quarter Fold Problem: Glue lines or backbone wetting not lined up. Description: For web presses that run magazines with glue or a backbone wetting solution along the spine of the quarter fold, it is important that all glue or water lines line up exactly, one on top of the other. Solution: Line up all the glue heads to the exact point where the chopper blade hits the copy. To ascertain this point, turn off the glue heads temporarily and see where the chopper hits. Then glue lines can be lined up to this point. Problem: Chopper table brushes not set properly. Description:  At the chopper table head stop, a set of brushes will push down on the lead edge of the copy. This assists with the following: Slows down the product Assists in preventing dog ears on the edges as it descends into the quarter fold nips Can correct the product that is coming in crooked. Solution: Stop and set these brushes evenly against the product.

Description:   This section covers everything from the former board down through to the exit from the press, but does not include any inline trimming or finishing. Please select one of the following problems: Gussets Wrinkles Crooked fold at Chopper / Quarter fold First fold (cross fold) Double Parallel or Delta fold Tears happening at Cross fold area Chopper / Quarter fold head stop Between former board and draw nips - coming soon Curl  - coming soon I can't find my problem. Start Over : Web Press Troubleshooting Guide

Please pick one of the following categories: Blistering Chalking Setoff Web Shrinkage I can't find my problem. Start Over : Web Press Troubleshooting Guide  

Description:   Passing through the heatset oven causes much of the paper moisture content to be lost.  As a result, the width of the web will decrease marginally.  The amount is proportionate to the width of the paper.  This is a normal process of heatset web printing.  Not to be confused with web growth  which actually happens at the printing units. Problem:  Too much width is lost when passing through the oven. Solution #1:  Purchase a component to add paper moisture content back into the paper.  They come standard with heatset presses and are necessary for the heatset printing process .  An example of this is the Goss Ecocool remoistening sytem . Solution #2:  Lower oven temperature.  Though it is not a solution, the web shrinkage effect can be minimized this way. I can't find my problem. Start Over : Web Press Troubleshooting Guide    

Definition:  The heatset oven is drying the ink, but a powder-like substance is deposited afterwards leaving setoff .  Additionally, this is accompanied by a reduced gloss appearance in the ink. Problem:  Oven temperature is too high. Description:  The ink reaches a point where solvents evaporate and leave the pigment and resin behind.  This is referred to as the flash-point.  However if the ink is cooked beyond that, the resins that help set the ink will lose their binding properties and break down.  This in turn will leave the pigments with very little to bind to.  To diagnose, hold your hand against the web where it is safe after the dryer and chills for a few seconds.  If a powder-like substance is left on your hands, you are over-cooking your ink. Solution:  Reduce oven temperature. I can't find my problem. Start Over : Web Press Troubleshooting Guide  

Definition:  This happens when moisture cannot escape the paper through the porous coating.  When it causes a small bubble upon exiting the heatset dryer oven, this is called blistering. Problem:  Printing heavyweight coated stock. Description:  The thicker the paper, the more moisture must escape.  There is only so much surface area to do so.  The increased amount of moisture in thicker papers combined with the fact that they are coated, allows less opportunity for moisture to escape in the drying process. Solution:  Run at the minimum dryer temperature required.  If that doesn't work, slow down the press.  Oven length is the determining factor as to how well a press will run this type of stock. Problem:  High moisture content paper. Description:  Too much moisture is in the paper.  Once again, on coated stocks, this problem will show up more often.   Solution:  A paper moisture content reader is expensive.  If you have one, check it against the paper manufactur

Definition:  Slurring takes place when slippage during the image transfer process. Problem:  Poor tension control. Description:  If the printing units have too much control of the nip, it may cause tension variations from unit to unit.   Solution:  Increase or decrease the tension at your infeed unit until it goes away.  Follow the basic tension principles for web offset printing . Problem:  Poor blanket tension. Typical slur patch Description:  The blanket is loose and not secured to the printing cylinder. Solution:  Torque the blanket to spec.  To not over tighten as this will cause other problems.  It should only be tight enough to prevent slippage and preserve it's properties . Problem:  Form oscillation. Description:  Form rollers that are designed to help with ghosting, will move from side to side.  This is good only to the extent that it will prevent ghosting .   Solution:  Many times the oscillation can be turned off by securing the ends of the rolle

Description:  Register is the alignment of colors that are printed in successive print units.  Problems can relate to software or printing unit prolblems. Problems with register are broken down into two categories: Transversal (Across the web) Problem:  Web growth or fan out. Description:  As the web travels from unit to unit, the size of the web width grows slightly.  This web growth or fan out causes the images not to register one on top of the other properly. Solution:  Compensate with bustle wheels behind each unit. Additionally, some prepress software will allow you to compensate by manipulating the size of the image. Problem:  Web wander. Description:  When the web is wandering from side to side, automatic registrations systems work too hard to compensate.   Solution:  Manipulate tension at your splicer to hold the wander steady. Circumferential (In the direction of the web) Problem:  Plates not mounted properly. Description:  Perhaps the cylinder gap

Definition: Lateral streaks are not to be confused with gear streaks .  These streaks do not coincide with the teeth of the gear that drives the plate or blanket cylinder.  They do however occur laterally from the gear to operator side of the cylinder. Problem:  Ink forms are set too heavy. Solution:  When ink forms are set too heavy, they will often hit the gap too hard.  This will cause a bounce and hence a slightly noticeable line across the printed image.  Lighten the forms to the manufacturers specifications. Problem:  Bad bearings in form rollers. Solution:  Check each form roller bearing thoroughly.  A bearing that is starting to wear will cause skips across the plate. Problem:  Main cylinder bearings. Solution:  Much like the roller bearings, the worn cylinder bearings will cause the same problem.  Inspect and replace as necessary. Problem:  Rollers are too hard. Solution:  Change rollers to something softer according to the manufacturers specs.  Generally, fo

Definition:  Mottle is caused by paper that is either linting too much onto the blanket, or a density that is too weak, causing the solids to look weak. Problem:  Blankets need washing. Solution:  Sometimes an automatic blanket washing system does not do enough.  Shutting down and scrubbing the blanket with water is sometimes necessary to remove all the lint buildup on the blanket.  This buildup causes solids too look like it has flakes in it. Problem:  Poor blanket to blanket or plate to blanket pressure. Solution:  Poor transfer can cause piling buildup which can effect how the solids looks.  Proper pressure can help prevent paper from building up on the blanket.  Check blanket heights, plate heights and bearer pressures . Problem:  Insufficient water flow. Solution:  Running the absolute minimum water is a purists ideal goal of ink and water balance .  However reality dictates that a little more water is necessary to prevent piling (from paper or ink) from building up

Definition:  Doubling, not to be confused with slurring, is caused by improper transfer of image from the blanket to the paper.  After the plate transfers ink to the blanket, it should then ideally all transfer to the paper.  If it does not, then the blanket revolves around to pick up the same dot, but on a slightly different position on the blanket.  The blanket then transfers a "double image" to the paper. Problem:  Too much packing under the blanket. Solution:  Check that you are the proper height over bearer on your blanket.  Essentially what is happening is that the blanket cylinder is travelling slightly faster than the plate.  A slight sliding action occurs and produces a double image.  Reduce the packing if necessary. Problem:  Improper bearer pressure. Solution:  Follow the procedure for checking and setting your bearer pressure properly. Problem:  Worn gears or bearings. Solution:  If your press is old, you need to consider this possibility.  Play in th

Please select your problem from the list below: dot gain doubling fanout (web growth) gear streaks ghosting mottle non-gear streaks register scumming slurring I can't find my problem. Start Over : Web Press Troubleshooting Guide

Description:   Wander can begin at different places on the press.  This refers to web wander that originates between the splicer and infeed. Problem:  Improper tension. Solution:  Web wander is almost always tension related.  Adjust tension up or down until it stabilizes. Problem:  Poor paper quality. Solution:  Try another position on the jumbo of the paper roll and make a comparison. Problem:  Idler rollers are not trammed properly. Solution:  Rollers that are not properly aligned will cause one side of the web to go baggy.  This in turn will cause wrinkles and web breaks.  Check all rollers carefully to ensure they are level and trammed. I can't find my problem. Start Over : Web Press Troubleshooting Guide

Whether you use a flying paster or a zero-speed splicer, many troubleshooting principles apply equally when it comes to wrinkling. Problem:  Rollers not trammed properly. Solution:  Tram all rollers even.  Check them for levelness and follow up with tramming. Problem:  Improper tension.   Solution:  Increase or decrease the tension based on the need.  Tension should really be based on the basis weight, but can require tensions out of range in some cases in order to avoid wrinkling. Problem:  Paper defect. Solution:  Sometimes the problem is in the paper making process.  Try using a roll that came from a different jumbo in the paper making machine.   Problem:  Debris on the idler rollers. Solution:  Sometimes splice tape will build up on the festoons or even the infeed rollers.  Take the time to clean them off as a regular part of your maintenance.   Problem:  Improper nip pressure. Solutions:  Some splicers have the infeed system built right into the splicer.  If th

Source of web breaks: Rollstand, flying paster or infeed. Problem:  Poor Paper Quality Solution:  Try a different position on the jumbo or a different paper altogether. Comments:  Though it is hard to see, when the paper rolls are weak, this will generally show up right away in the beginning of the web press.  Check the edges of the roll.  Paper defects are common.  Sometimes nicks can occur or the slitter at the paper mill was simply dull.  Also, hold the paper up to the light and check for pin holes. Problem:  Foreign Material On Idlers Solution:  Clean off idler rollers.  Carefully check each one for dents that could cause a raised spot and break through the web. Comments:  Generally a splicer can have two sided tape build up on the idlers.  Splice after splice can cause this buildup.  Or perhaps a pieces of tape wrapped around the roller to take out wrinkles.  Whatever the case, check the idlers carefully for any raised spots on the idlers from buildup or damage. P

The following troubleshooting guide applies specifically to web breaks occurring at the moment of the splice. Problem:  Poor or outdated splice tape. Solution: Splice tape has an expiry date and must be stored at a cool range of temperatures in order to retain its properties.  Try a different batch of tape. Problem:  Damaged paper. Solution:  Enough paper must be stripped off the roll before mounting it. This shouldn't be much.  However any nick will cause the brake.  Inspect rolls carefully. Problem:  Temperature of paper at splice.   Solution:  Rolls that have been in cold storage do not work well on splices.  The various tapes in the industry are good, but when the web is very cold, the splice will not always stick well.  Some printers will get a device especially designed to heat the core of the roll so that the temperature will be just right.  Either heat up the temperature of the paper in storage or buy a core heater.  Probably the latter has the quickest payba

I may not know everything about printing, but I can offer my advice if you leave a comment below.  I can usually respond within a day. Or you can start over: Web Press Troubleshooting Guide

Select the type of problem: Web Breaks (on splice) Web Breaks (not on splice) Wrinkling Web Wander I can't find my problem. Start Over : Web Press Troubleshooting Guide

This web press troubleshooting guide is a work in progress.  It is updated continuously as we face issues in our own press room.  As we face more problems on our web presses, I hope that it will become even more valuable.  Please subscribe to receive updates.  I welcome your input and suggestions. To begin, please select the part of the press where the problem originates: Splicer / Infeed Printing Units Oven / Dryer / Chills Superstructure Folder Finishing line - soon to come Resources: Offset Printing Explained

I would like to compile a comprehensive troubleshooting guide for pressmen.  My hope is that it will encompass each part of the printing press as well as each raw material used in offset printing. Please bear with me as this project will take several days to complete.  I will have a main troubleshooting page where you can start and narrow each problem down to something specific.  I'm hoping to get feedback so that I can keep adding to it.  The more I can add and feedback I can get, the more valuable it will become.  I insist though that those who give feedback will only be those that actually work on offset printing equipment or are directly connected to that production environment. I'm tired of looking for solutions from sources that give ridiculous answers to problems or just speak in generalities.  When we have a problem, I pick up a GATF guide or some other publication and I find it not very useful.   I hope to provide video, pictures and real life examples of how o

Most Americans have a Jack Armstrong image of themselves and their peers.  Jack Armstrong, for some of you youngsters, was the all-American boy - forthright, straight shooter, brave, strong, and proud.  Jack would never, ever, take advantage of anybody.  He was the consummate doer of good deeds who would slay the forces of evil and the perpetrators of sin and corruption.   This image of purity and goodness has been a barrier in the real world of management and particularly in the field of motivation .  Nobody but nobody wants to come out and say it, but fear is the single most effective motivator.  No manager will admit to having that tool in his arsenal of weapons to get people to work harder.  That would not be American and kind of dirty.  It would be like stealing your mother's welfare check to play the horses. Why is fear the unmentionable factor in a manager's lexicon?  One reason is that most managers today wouldn't have the balls to carry out the threat that gener

Some printers have great working conditions for their pressmen.  I've had the privilege to work at a few and I would like to share some ideas of what I feel are easy to do.  Of course money is a great motivator, but that is another topic I've covered before.  Here are some easy ideas that require minimal investment.  Ideas that even the cheapest employer should consider. 1.  Proper matting.  Standing on concrete all day is a killer on the back.  It doesn't have to be much, just around the area where people are standing all day. 2.  Cleanliness.  There is a certainly a connection between a clean work environment and employee satisfaction.  Keep the place clean and morale will improve. 3.  Proper safety equipment.  Show you care.  Even if nobody wears it, you may even avoid a lawsuit for doing the right thing. 4.  Fans.  Most that work in this industry do not work in comfortably air condition offices.  Fans are not expensive.  Buy some good ones and put them in strat