Two Cases of Commercial Printing Fault Analysis

1. There are ink particles and paper hairs on the prints

Symptoms: When a color group prints seals, there are 0.5mm to 2mm diameter ink particles and paper sticking phenomenon on the seal arc.

Upon inspection, the ink and paper powder on the blanket and the printing plate are thickly stacked, and the white side of the paper powder is severe at the position corresponding to the edge of the blanket. The initial judgment is due to paper looseness. After washing blankets and printing plates, the speed of printing was slowed down. The problem was not completely solved. The same problem reappeared after about one hour. So the main reason for the judgment is ink. The use of ink knife ink tank found that the ink flow is very poor, then add 0 # varnish and mix thoroughly (about 30%), reboot, the problem no longer exists.

Cause of failure: Long-term printing, ink in the ink tank fluidity worse, sticky, resulting in easy to grain from the ink, and easy to stick paper powder.

Matters needing attention: The machine must diligently ink fountain for a long time printing, if necessary, add appropriate amount of additives to improve the performance of the ink.

2. Superfluous ink lines appear on the print
Symptom: When the ticket is printed, a redundant ink line appears in the form.

The inspection found that the ink line was not present at the position of the printing plate, and the factors such as squeezing the mouth and the blanket were eliminated; the full graphic was clear and there were no other stains, and the dirty printing was excluded; the ink was checked, and the ink roll was heavily accumulated. Big. Then wash the printing plate and the blanket, close the ink roller and print it. The ink line will appear again after a few minutes. Wash the ink, re-up less ink, slightly reduce the fluid volume, and then boot, the problem is solved.

Cause of failure: The ink roller has a large amount of ink. When the ink is deposited, the pressure on the printing plate is heavy. A thicker ink line is printed on the plate. Although the dampening solution has washed away some of the ink, it cannot be completely washed by the firmly adhered ink line. go with.

Matters needing attention: When the rotary machine is inked, it should be small ink and small water. Do not start large ink and water, leading to serious emulsification of ink and other failures.

Source: Printing Technology