Anti-overprinting is especially obvious when printing at medium and low speed. The phenomenon of reverse overprinting is greatly reduced during high-speed printing. The key to solving the problem of reverse overprinting is to analyze the causes. On the printing plate of the printed ink, it enters the back-color ink tank and changes the color of the back-color ink, which eventually leads to the inability to continue printing. For example, yellow ink gradually becomes light green, and red ink gradually becomes purple.Generally, it can be solved from the following aspects: 1, Adjust the ratio of the dilution solvent of the back-color ink to reduce the solubility of the back-color ink to the front-color ink when the front-color ink is in contact, that is, when diluting the back-color ink, add a part of isopropyl alcohol and use as little toluene as possible. 2, Increasing the printing speed can significantly reduce the contact time between the back-color ink and the front-color ink, which is why the reverse overprinting is especially obvious during low-speed printing, but there is basically no reverse-overprinting phenomenon in high-speed printing. 3, Adjust the formula composition of printing ink. First of all, it can be used to improve the front color ink in theBOPPThe method of adhesion on the film, so that when the two layers of ink are in contact, the front color ink still adheres to the film.BOPPon the film, inCL~PPIn the ink of the system, it is generally possible to increase theCL~PPcontent is resolved. Secondly, the drying speed of the front color ink can be increased, and the drying tunnel temperature of the front color ink can be increased to prevent the presence of a small amount of mottled solvent in the ink film.
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