There is a big difference between ink film formation and solvent ink film formation. After the solvent ink is transferred to the film, the solvent evaporates, and the remaining resin accumulates into a uniform ink film. Due to the existence of the emulsion, the first stage after the ink is transferred to the film is the accumulation of particles, and then they are closely arranged with the volatilization of water, and then deformed, and finally the ink film is formed. The ink film formation of solvent ink has only 2 stages, while the ink film formation of ink ink has 4 stages. The formation of different ink films constitutes several fundamental quality problems in the application process of ink, that is, the leveling of ink on the ground, the smearing of ink due to insufficient surface drying, and the pinhole defects of ink.
Field leveling
The field leveling problem, that is, the original characteristics of the gravure printing field, which are dense and flat, are gone, and regular white spots appear in the field printing.
The fundamental solution is to add a co-solvent, which is used to improve the deficiencies in the emulsification process of the water-based resin and reduce the side effects of the emulsifier in the water-based emulsion manufacturing process. During the drying process of the ink film, the co-solvent can dissolve, deform and fuse the polymer particles into a continuous ink film, which can dissolve and temporarily plasticize the resin, and can significantly improve the leveling on the ground. The amount of co-solvent added should not exceed 5%. Excessive co-solvent will soften the ink film and affect the strength of the ink film.
Gravure can be used to improve gravure solid leveling. The two left and right columns in the figure below are electrogravure and laser gravure respectively. Electro-engraving gravure can be improved according to the angle characteristics of the channel. For example, the channel at the 30° angle appears earlier than the 45° angle, and the channel at the 60° angle is difficult to appear. The laser gravure itself probably has no communication, but it can be made through custom editing of dots. Communication improves field leveling.
