Three kinds of printing failure prevention

A failure

The retraction of the ink film on the surface of the printed product exposes the surface of the substrate to a large area of ​​the printed surface. This phenomenon is called shrinkage. This is due to the poor wetting of the substrate by the printing ink. If the surface of the substrate contains oil stains, plastic surfaces, and electrodeposited printing ink surfaces that contain too much anti-scratch additives on the surface of the substrate, the printing plate is not concentric or eccentric, and the direction of advancement shrinks (not in the longitudinal direction), often causing partial shrinkage (breakage). ).

Preventive measures: Before printing, the surface of the substrate should be subjected to strict degreasing treatment, and special printing inks with low surface tension should be used.

Failure two pits and pits
Since the wet ink film of the printing ink is accompanied by foreign particles, these foreign particles are spread on the wet ink film and repel the ink around them to form a pit-like shape, which is also called a “pocket”. Obviously, it can be seen that there are foreign particles in the center of the pit, also known as "pitting." This phenomenon does not generally reveal the substrate of the substrate.

Preventive measures: Control the environment, improve the cleanliness, ensure the purity of the solvent or diluent, and have no foreign materials.

Fault three thick sides
After printing, the corners of the ink film are particularly thick and the finished product looks like a frame, which is called "thick edge". This is due to the fact that the solvent of the wet ink film on the corners evaporates faster than other locations, causing the ink concentration at this location to be too high and the temperature to be lower than elsewhere, forming a high surface tension area, causing the adjacent ink to flow to the corners, and thickening the ink there. membrane.

Preventive measures: Improve the thixotropy of printing inks, reduce printing pressure, and add appropriate amount of rheological additives.