Protruding spots like fountains or craters appear on the ink layer or varnished surface of the printed product, and sometimes the entire pattern is present. The printing surface is rough and the gloss is reduced.
The surface of the ink dries too fast. The heat first strongly acts on the surface to form a dry film. The solvent in the lower layer is temporarily sealed. When it continues to be heated, the internal solvent must escape to the outside. When the energy reaches the level of breaking through the surface film, it will be ejected, thereby forming shrinkage cavities.
1. Appropriately add leveling agent to printing ink;
2. Use solvents with low surface tension;
3. Wetting the surface of the substrate;
4. Control the temperature and humidity of the printing environment;
5. Choose a suitable interpreter;
6. Reduce the surface tension between the printing ink and the printing carrier, so that the ink and the carrier have good wettability, so that it will not form a surface tension gradient with the substance that causes shrinkage;
7. Adjust the solvent evaporation speed, reduce the viscosity, improve the fluidity of the ink, and extend the leveling time.