In the field of carton printing, ink printing has long become the mainstream printing method. Both large, medium and small carton enterprises have chosen to buy water-based flexographic printing machines as their printing equipment. Similarly, the problems around the water-based printing press have attracted more and more attention from people in the industry.

Most carton manufacturers have printing die-cutting slotting machines integrating printing, slitting and indentation production functions. The equipment is simple and convenient to operate, relatively high degree of automation and easy to control quality. It plays a certain role in the carton production process. However, if the equipment is aging and the machine is improperly adjusted, some faults are easy to occur during printing, The common printing problems encountered in the production process are analyzed by category.

The quality problems of dirty, paste or unclear imprinting of local graphics and text occur in the layout

1. Quality failure caused by poor machine imprinting related parts

When the plate roller shaft head, embossing roller shaft head, transmission shaft, gear and important components associated with embossing are worn and loose, the plate roller or embossing roller will jump or slide during the embossing process. Due to the unstable pressure, the contact between the printing plate and the paperboard is abnormal, resulting in the problem of plate pasting or unclear local graphic imprinting on the printing surface of the paperboard. Through careful observation and analysis, find out the exact location of the fault, take corresponding measures to deal with it, repair the worn and loose parts and eliminate the fault phenomenon.

2. Quality failure caused by poor inking roller

When the inking roller shaft head is loose and the inking roller body is bent, deformed or damaged, it will also cause dirty layout, paste version or unclear local graphics and text. Find out the causes and take corresponding measures to deal with them, so as to 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 fault phenomenon.

3. Quality failure caused by improper adjustment of pressure roller

If the position of the pressure roller is too high or too low, so that the contact with the corrugated board is too tight or too loose, there will also be dirty plate, paste plate or unclear picture and text imprint. Adjust the pressure roller to a suitable position to make the gap between the pressure roller and the roller adapt to the thickness of the paperboard, so as to ensure the position of the printing plate and avoid the occurrence of this fault.

4. Quality failure caused by improper color sequence

If the pictures and texts with full layout are arranged in the first color group for printing, when the corrugated board enters the printing process of the next color group mechanism, due to the large amount of ink and slow drying speed of the printed pictures and texts of the first color group of the paperboard, it is very easy to transfer the imprint and dirty the layout. In order to prevent this disadvantage, the layout with small area should be arranged in the first color group printing, and the layout with large area should be arranged in the subsequent color group printing, so as to avoid the phenomenon of dirty version caused by imprint transfer.

5. Quality failure caused by uneven plate thickness

When the thickness of rubber plate is uneven, the height difference of printing plate will appear. In order to avoid this bad situation, the plate can be made into several small pieces by sporadic plate making (referring to the plate making process without plate making core in order to save rubber plate), and the same plate shall be made separately, In this way, its thickness difference is relatively small. If the thickness difference of the prepared rubber plate exists, it can be compensated by multiple adhesive tape layers on the back of the locally thin printing plate, so as to keep the whole printing plate basically the same thickness and ensure the uniformity of printing pressure and printing ink on the plate.