Jan. 09, 2023
In addition to packaging goods and facilitating transportation, cartons also play the role of beautifying goods and promoting goods. Therefore, the printing quality of cartons is very important. So, what are the common quality problems and solutions in carton printing?
1. Bad printing related parts of the machine
Problem: When the shaft head of the printing plate roller, the shaft head of the embossing roller, the transmission shaft, the gear, and the important parts associated with the embossing are worn and loose, the printing plate roller or the embossing roller will be generated during the embossing process. Jumping or sliding phenomenon, due to unstable pressure, the contact between the printing plate surface and the cardboard is abnormal, resulting in the problem of paste on the printing surface of the cardboard or unclear imprinting of partial graphics and texts.
Method: 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. Improper adjustment of the 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 dirty plates, paste plates or unclear imprints of partial graphics and texts.
Method: Adjust the pressure roller to a suitable position, so that the gap between the pressure roller and the roller is suitable for the thickness of the cardboard, so as to ensure the position of the printing layout and avoid the occurrence of this failure phenomenon.
3. Defective ink form roller
Problem: When the shaft head of the inking roller is loose, and the roller body of the inking roller is bent, deformed or the surface is damaged, it will also cause the layout to be dirty, pasted or partially unclear.
Method: The reason should be found out, and corresponding measures should be taken to deal with it, so that the contact condition between the ink form roller and the printing plate is maintained uniform and suitable, and the damaged ink form roller can be replaced to eliminate the fault phenomenon.
4. Uneven thickness of corrugated cardboard
Problem: When the surface of the formed corrugated cardboard has sunken marks of artificial damage, the paper surface of the sunken part will also have quality defects with unclear imprints. If it is compensated by increasing the printing pressure in an all-round way, it is easy to cause quality problems such as blurring of the text and line layout.
Method: In order to avoid paste on the layout, during the stacking and handling of corrugated cardboard, care should be taken to move, place, and press lightly (to control the stacking height), and do not use bad production habits such as throwing, smashing, and pressing for handling.
5. Uneven plate thickness
Problem: When the thickness of the rubber plate is uneven, there will be height differences in the printing plate layout. Where the layout is high, it is easy to paste the plate, and where the layout is low, it is easy to have incomplete ink, resulting in unclear imprints.
Method: Sporadic plate-making can be used to make plates into several small pieces, and the same plate should be used to make them separately, so that the difference in thickness is relatively small. If the rubber plate has been made, if there is a difference in thickness, it can be made up with a multi-adhesive cloth layer on the back of the partially thin printing plate to keep the thickness of the entire printing plate basically the same, ensuring uniform printing pressure and ink on the layout.
6. Improper color sequence
Problem: If the graphics and texts with a full layout are arranged in the first color group for printing, when the corrugated cardboard enters the printing process of the next color group mechanism, due to the large amount of ink and slow drying speed of the printed graphics and texts in the first color group of the cardboard, It is easy to transfer the imprint and cause the layout to be dirty.
Method: Arrange the small-area layouts in the first color group for printing, and arrange the large-area layouts in the subsequent color group for printing, which can avoid the phenomenon of dirty plates caused by imprint transfer.