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How to solve the problem of printing deinking

Printing deinking is the phenomenon that the metal ink roller is oxidized by the dampening solution to repel the ink. The ink on the ink roller is not evenly flowed, and some places do not stick to the ink, especially the metal roller is more serious, which often causes the printing plate to have a blank area, that is, the ink in the ink fountain of the offset printing machine is difficult to pass to the ink fountain roller. Deinking is generally caused by the ink being sensitive to the dampening solution (hydrophilic emulsification) and the yield value of the ink is large, the thixotropy coefficient is high, and the cohesive force is very strong, the ink viscosity is small, but the consistency is large.

The problem of ink viscosity is one of the biggest causes of deinking. The high viscosity of the ink will slow down the drying of the ink. When the ink is not dried quickly, it is easy to produce deinking. Therefore, reducing the viscosity of the ink is the best way to overcome the deinking. If the color is deviated after the viscosity is lowered, the toner content of the ink can be increased to ensure the correctness and stability of the ink color.

Followed by the wear resistance of the ink, the wear resistance of the ink is mainly reflected in the cohesive force and adhesion of the ink. When the ink cohesion and adhesion are reduced, the wear resistance of the ink is deteriorated, which is closely related to the ink itself. If the ink has dried after printing, and the ink is wiped off by hand or paper, there is a serious deinking phenomenon, which means that the ink has poor abrasion resistance, which requires an increase in the anti-wear agent or a new ink production.

When the paper has low water absorption, the water absorption of the ink is naturally lowered, and the ink floats on the surface of the paper to easily cause deinking. If the paper is known to have poor water absorption, it is necessary to start from the tile line. Firstly, the heat of the facial tissue is increased, and the heat of the paper is used to damage the facial fiber and the paper sizing layer, thereby improving the ink absorbing property of the paper, and increasing the amount of the penetrant used in the printing, thereby preventing printing better. Deinking occurs.

In summary, the occurrence of deinking is common, and the reasons for each deinking are also different. Only when the real reason is found and the appropriate method is sought to improve, the effect will be better.