Printing density uneven solution

(1) Definition: refers to the failure of a certain part of the print product concentration or the density of each print product does not match.

(2) There are three main forms:
a) uneven density on one side of the printed product;
b) Gradual variation in the concentration of printed matter during printing results in uneven density;
c) Inconsistent density occurs after printing several sheets.

(3) Causes and Remedy 1 Density unevenness on one side of the printed product:
• There is a large difference in the thickness of the plate or the thickness of the double-sided tape.
• The back of the plate or the surface of the plate cylinder body is partially uneven or has foreign objects.
The unevenness of the density in the left and right direction of the printed product:
• The degree of parallelism between the plate cylinder and the impression cylinder or the plate cylinder and the anilox roll is poor, causing the balance of transverse pressure between the rollers to be lost.
• Scraper edge and anilox roll surface tangent defect.
· The blade edge has defects.
• The thickness of the printing plate and the double-sided tape has a large error in the transverse direction of the roller.
Therefore, the above links should be tested and adjusted.

2 Gradual changes in the density of prints during printing result in uneven density:
·Ink performance changes?
• The main lubrication area is poorly oiled.

3 After printing several sheets, the density is not uniform, or the density unevenness occurs when the printing is recommenced after printing is stopped:
· Overprinting is not allowed or caused by ink sticks.
· The performance of the ink in the ink fountain has undergone major changes, such as the reduction of the solvent and the deposition of the pigment.