In the traditional printing process, the quality of the rubber roller is crucial to whether the printed product can obtain the ideal ink color. Machines that print color products are generally equipped with three components: ink transfer rollers, ink distribution rollers and ink application rollers. The ink transfer rollers and ink application rollers have a greater impact on the quality of printing ink.

　　The quality of the rubber roller is mainly reflected in the aspects of elasticity, viscosity, roundness and surface finish. Among them, the viscosity mainly affects the intensity of the ink color. During the printing process, the rubber roller should maintain a certain viscosity to ensure that the ink applied to the plate is consistent in each printing cycle. However, in the actual production process, the viscosity of the rubber roller is not stable. The reasons are: first, due to the increase of paper dust in the ink; second, the tackifier (ie glycerol) on the surface of the rubber roller will increase with the increase of temperature and use. As time goes by and dissipates, the viscosity of the rubber roller surface gradually decreases, and the ink absorption performance also decreases accordingly, thus affecting the balance of the ink color of the printed product. Therefore, when printing color products, polyurethane rubber rollers with relatively stable quality should be used. If a large number of products are printed, the rubber roller should be cleaned in a timely manner to remove impurities on the rubber roller to ensure the printing quality of the product.