Common quality problems and solutions in carton printing
Common quality problems and solutions in carton printing
1. Defective parts related to machine imprinting
Problem: When the plate roller shaft head, impression roller shaft head, transmission shaft, gears, and important parts related to imprinting are worn or loosened, the plate roller or impression roller will jump during the imprinting process. Or sliding phenomenon. Due to the unstable pressure, the printing plate surface and the cardboard are not in normal contact, resulting in the problem of smearing or partial imprinting of the cardboard printing surface.
2： Improper adjustment of pressure roller
Problem: The position of the pressure roller is too high or too low, so that the contact with the corrugated cardboard is too tight or too loose, and there will be a dirty version, a stale version or a partial imprint of the image and text.
Method: Adjust the pressure roller to a suitable position, so that the gap between the pressure roller and the roller is compatible with the thickness of the cardboard, so as to ensure the location of the printing plate and avoid the occurrence of this malfunction.
3, the inking roller is bad
Problem: When the inking roller shaft head is loose, the inking roller body is bent, deformed, or the surface is damaged, it will also cause the layout to be dirty, or the partial graphics are not clear.
Method: Find out the cause, take corresponding measures to deal with it, maintain uniform and appropriate contact conditions between the inking roller and the printing plate, and replace the damaged inking roller in order to eliminate the malfunction.
4： Uneven thickness of corrugated cardboard
Problem: When the surface of the formed corrugated cardboard is damaged by human-made dents, the paper surface of the dented part will also have quality defects with unclear imprints. If the printing pressure is increased in an all-round way to make up, it is easy to cause the quality problems of the text and line layout to be blurred.
Method: In order to avoid smearing of the layout, the corrugated cardboard should be handled lightly, placed lightly, and lightly pressed during the stacking and handling process (the stacking height must be controlled), and bad production habits such as throwing, smashing, and pressing should not be used for handling.
5：Uneven printing plate thickness
Problem: When the thickness of the rubber plate is uneven, there will be a difference in the height of the printing plate, where the layout is high, it is easy to paste the plate, and the place where the layout is low is prone to incomplete ink, resulting in unclear imprints.
Method: The method of sporadic plate making can be used. If the plate is made into several small pieces, the same plate should be used to make separately, so that its thickness difference is relatively small. If the rubber plate has been made, if there is a difference in thickness, a layer of viscose cloth can be used on the back of the partially thin plate to make up for it to keep the entire printing plate basically the same thickness to ensure uniform printing pressure and ink on the plate.
6：Improper color order
Problem: If the graphics with a full layout are arranged in the first color group for printing, when the corrugated cardboard is printed in the next color group, the printing graphics and text of the first color group on the cardboard have a large amount of ink and a slow drying speed. It is easy to transfer the print and cause the layout to get dirty.
Method: Arrange the small-area layout in the first color group for printing, and arrange the large-area layout in the subsequent color group for printing, which can avoid the phenomenon of dirty printing caused by imprint transfer.