Failure analysis of "imprint shortening" in the printing process

The phenomenon of lengthening or shortening of prints is more common in the printing process. Most of these failures are related to paper, printing pressure, the nature and material of the liner, and gripping teeth. The author encountered a special case.

Fault phenomenon

The operation of a four-color offset printing machine has been good, but when switching printing operations, the set of printing plates that were just installed showed a marked shortening of the second-color printing plate (cyan version).

Failure analysis and elimination

After repeatedly checking the pressure, gripping teeth, and lining, no problems were found. The blue plate was reprinted and printed after installation. The failure remained the same, so it was suspected that the machine had serious problems. The author carefully listened to the introduction of the relevant operators in the workshop, and carefully checked the printed sheets. It was found that the axial and radial directions of the green print were significantly shortened, and the other three-color overprints were very accurate. After that, the machine was briefly checked again, and basically no problems were found. According to the condition of the printed sheet and the machine, it is not certain that it is a malfunction of the machine, or it may be caused by other reasons, so to avoid unnecessary trouble, we did not adjust the machine blindly. When studying the specific operation details with the relevant operators in the printing and printing workshop, the author believes that there are no problems with the operator's operation procedures and processes, and the film is completely accurate.

So what is the problem? It turns out that this set of printing plates was produced a week ago, and has not been used due to production scheduling. The plate-printing staff found that the green plate could not be used due to scratches, so he made another photo. In the work, I often encounter the damage of the printing plate and make up the sun, and there is no problem. However, it was a rainy day a week ago, and the air was very humid for a few days, so it may be that the original film was stretched due to moisture, resulting in the lengthening of the four printing plates. After the weather improved, coupled with the temperature of the printing workshop, the humidity control measures were not very effective. When re-printing the green version, the film was shortened due to the dry and shrinking weather. In order to confirm this judgment, we found the scratched plate and the newly-printed plate to compare with the film, and found that the scratched plate was longer than the film and the newly-printed plate. Then the black, magenta, and yellow printing plates on the machine were all removed and compared with the printed sheets. The results confirmed the author's judgment. After reprinting and trial printing, the fault is eliminated.

Fault revelation

the first. Film also has properties similar to that of paper that tends to stretch after being damp. Second, failures in the printing process must be carefully analyzed and the cause must be analyzed. It must be distinguished whether it is a machine failure or a process and operation failure. It must not be followed blindly, otherwise it may cause serious consequences. Thirdly, the operator should study hard, accumulate more, and have a wealth of professional knowledge in order to eliminate the fault, especially when dealing with such seemingly complex but simple faults.

ZENGHUI PAPER PACKAGE is a good Food Packaging manufacturers and suppliers with good reputation, we have our own food packaging  box factory, we are able to provide our customers varieties of chocolate boxes with good quality and reasonable price. such as handmade rigid chocolate boxes,foldable chocolate boxes,card chocolate boxes.etc.Welcome to wholesale products from us.

Chocolate Box

White Chocolate Boxes,Luxury Chocolate Box,Chocolate Paper Box,Chocolate Food Box

Zenghui Paper Package Industry and Trading Company , https://www.packagebox.nl

Posted on