Postpress quality and processing

Common problems and treatment methods for the varnishing process In the post-press processing process, the varnishing process can not only increase the surface appearance of the finished product, but also can play a protective role. The following is a brief analysis of some of the problems that arise during the glazing process.
If the gloss of the film is poor, if it is a problem with the quality of the coating, you should consider changing the quality of the coating according to the process and economic requirements; if the coating is too thin, the coating amount is insufficient or the coating oil concentration Small, high roughness, strong absorption of the printed surface is not easy to fill up, you should increase the amount of coating, improve the coating concentration, or a layer of light before the end of processing primer, and then coating , It may also be the coating coating drying and calendering temperature is low, the calendering pressure is small, the operation should adjust the process parameters, increase the temperature, increase the pressure; also estimated to be the device itself, if the pressure The optical steel belt wears, and the smoothness of the gloss decreases, which is to repair and improve the surface condition of the calendered steel strip.
After calendering, the blank part of the printed product is a light-colored part, and the light-colored part of the printed matter has a dissolving effect on the ink layer. This requires changing the type of the coating oil or changing the solvent composition; if the ink is poorly dried, the ink layer is resistant to dissolving. Well, it is necessary to improve the ink drying conditions, such as ink drying and then coating, reducing the amount of solvent in the coating solvent for the ink solubility; layer is not completely dry, the film residual solvent is high, it is necessary to improve The coating drying temperature or speed is reduced, the drying time is prolonged, and the residual solvent content in the coating is reduced.
Film bubbling in the process of calendering, the pressure is too large, the temperature of the calendered strip is too high, so that the glazed layer is partially softened, which requires appropriate reduction in the pressure and temperature of the calendering; it may also be the varnish and calendering The process conditions do not match, so that after the glazing layer on the surface of the print is cooled, the peeling force is the same as that of the upper belt, the process conditions need to be changed to match the glazing oil, the calender speed is reduced, and the glazing layer is the same as the upper belt Peeling force between.
After the calendering of the printed matter, the surface is subject to high fracturing temperature, which causes the dehydration of the printed matter in the calendering process to be excessive, the moisture content is reduced, and the paper fibers become brittle, the working temperature of the calendering should be reduced, and effective measures must be taken to maintain the prints. A certain amount of water content; Excessive pressure in the calendering can reduce the extension and plasticity of the printed matter, and the ductile denaturation can reduce the pressure in the calendering. If the post-processing of the varnish is poor, it should be re-selected. The better the varnish; After the selection of the processing conditions is not appropriate, you can adjust the post-processing conditions to match the suitability of the printed calender after printing.