Failure analysis of blot shortening during printing
We are a big printing company in Shenzhen China . We offer all book publications, hardcover book printing, papercover book printing, hardcover notebook, sprial book printing, saddle stiching book printing, booklet printing,packaging box, calendars, all kinds of PVC, product brochures, notes, Children's book, stickers, all kinds of special paper color printing products, game cardand so on.
For more information please visit
http://www.joyful-printing.com. ENG only
http://www.joyful-printing.net
http://www.joyful-printing.org
email: info@joyful-printing.net
The elongation or shortening of the blot is common in the printing process. Most of these failures are related to paper, printing pressure, the nature and material of the liner, and tooth decay.
Fault phenomenon
The operation of a four-color offset press has been good, but when the printing press was switched, the set of plates that had just been installed showed a noticeable shortening of the second color plate (green plate).
Fault analysis and elimination
Repeatedly checking the pressure, fangs, and lining, no problems were found, the sun-printed version was re-sealed, and the test was printed after the installation. The fault remained. The operator carefully inspected the printed sheets and found that the axial and radial directions of the green prints were significantly shortened, while the other three-color overprints were very accurate. A simple check on the machine is basically no problem. Depending on the condition of the sheet and the machine, it is not certain that the machine is malfunctioning and the machine cannot be adjusted blindly. After researching with the relevant operators of the printing plate and printing workshop, it is considered that there are no problems in the operation procedures and processes, and the film is completely accurate.
So where is the problem? It turns out that this set of plates was made a week ago and has not been used. Before the machine was found, the blue plate was found to be unusable due to scratches, so it was added to the sun. In the work, I often encounter damage to the printing plate and make up the sun. There is no problem. But a week ago it was rainy days, and the air was very humid for a few days, so the original film was stretched due to moisture, causing the four plates to stretch. After the weather improved, coupled with the temperature and humidity control measures in the printing shop, the film was shortened due to the dry and shrinking of the film. In order to confirm this judgment, the scratched plate and the new sun-printed plate were compared with the film, and it was found that the scratched plate was longer than the blot of the film and the newly-printed plate, and then The black, magenta, and yellow three-color plates on the machine were all removed and compared with the printed sheets to confirm the judgment. After reprinting, try to print and troubleshoot.
Fault revelation
First, the film also has a property similar to that of paper which is easily elongated after being damp.
Second, if there is a fault in the printing process, you must carefully analyze the cause and distinguish whether it is a machine fault or a process and operation fault.
Third, operators should learn and accumulate at times, and have a wealth of expertise to eliminate many detours when troubleshooting, especially when dealing with such seemingly complex but simple faults.