How to solve the problem of reverse printing in the printing process

Anti-envelope printing is particularly noticeable at low to medium speeds. The phenomenon of reverse printing at high speeds is greatly reduced. The key to solving the problem of reverse printing is to analyze the reasons for clear printing. In reverse printing, the ink is generally printed before the ink is reversed. On the printing plate of the ink, it enters the ink tank of the posterior color, changes the color of the ink of the latter color, finally causes the printing to be unable to continue, if the yellow ink gradually turns into the light green color, the red ink turns into the purple color gradually.

Generally can be solved from the following aspects:

1. Adjust the ratio of the ink dilution solvent to reduce the dissolving ability of the ink after the color ink is in contact with the ink of the preceding color. That is, when diluting the color ink, add a part of isopropyl alcohol and try to use less toluene. ;

2. Improve the printing speed. Increasing the printing speed can significantly reduce the contact time between the back color ink and the front color ink. This is especially obvious when reverse printing is used at low speed printing, and there is basically no reverse printing phenomenon in high speed printing. This may be limited by the printing equipment and the printing environment during actual printing;

3, adjust the composition of printing ink formulations

First of all, you can use the method of improving the adhesion of the ink on the BOPP film, so that when the two inks are in contact, the ink of the front color is still attached to the BOPP film. In the ink of the CL-PP system, the CL-PP can generally be increased. Content is solved. Secondly, the drying speed of the ink of the preceding color can be increased, the temperature of the drying path of the ink of the preceding color can be increased, and the presence of a small amount of non-volatile solvent in the ink ink film can be prevented.