In the packaging box printing, in order to set off the high quality of the graphics and the pursuit of high added value of the goods, people often use spot colors before printing the graphics. In order to obtain a bright and bright effect, it is generally necessary to take two printing, increase the printing pressure or increase the amount of dry oil. Although this completely covers the defects on the substrate, drying too quickly will often lead to the surface of the ink after the film is formed, just like glass, resulting in uneven or completely unprinted ink, showing beads or only showing a very weak color. Because the ink adhesion is not strong, sometimes it can even be wiped off. The printing community calls this phenomenon ink film crystallization or vitrification, mirrorization and so on.

1. Use a fast-drying ink overprint containing more solvents (printing the second color without waiting for it to dry thoroughly, although the effect is better, but this method is time-consuming, time-consuming, costly) The solvent used can immerse and soften the ink film layer of the bottom layer (but sometimes it will not help).

2. Grasp the overprinting time, and print the second (secondary) color as quickly as possible after the previous color printing.

3. Add some polymerizers (such as hydroquinone) or slow-drying materials (petrolatum, lanolin, wax additives) to the packaging box printing ink.

4. Different basic colors that are easy to overprint can be used in the pattern design of the printing decoration of the packaging box.

5. Cobalt desiccants should be used less in the ink formula.

6. The full-fledged resin-type binder that dries quickly can be used to reduce the amount of desiccant in the ink.

7. Enhance the adhesion of the second color ink, the purpose of which is to destroy the crystallized ink film. If the use of zero ink or alkyd resin, epoxy resin and polyamide resin is a material with large adhesion, adding to the ink can enhance its adhesion, but the miscibleness of these resins and offset ink is not good, can not be added more, because too much addition will often dilute the color of the printing ink of the packaging box, and too little of its effect will not be good.

8. Add an organic solvent to the printing ink of the box to dissolve the crystallized ink film layer. This is one of the methods commonly used by printing manipulators, but the crystallized ink layer has become a smooth ink film layer of the main mesh structure that is not easy to dissolve, and the effect is not good when too much.

9. Add alkali or soap to the box printing ink to enhance the polarity, making it easier to print. But at that time, although it seemed to be printed, it was not attached firmly after drying and it was easily erased.

Comprehensive nine treatment methods and preventive measures, the only way to make the packaging box printing graphic quality is best to grasp the dryness of the ink in printing, and not to let the ink become too dry to start printing the second color for the best