Requirements for printing rollers

Printing rollers are divided into hard rollers and soft rollers, mainly used for printing. In addition, printing rollers have good ink transfer and ink application performance, and good ink affinity can ensure high-quality printing. The following introduces the requirements for printing rollers.
1. Hardness and elasticity: The ink rollers on the offset printing press are alternately arranged by printing rollerss and metal (or hard plastic) rollers. In order for the printing rollers to come into contact with a metal (or hard plastic) roller under a certain contact pressure and transfer ink well, the printing rollers must have good elasticity and compression deformation, and the surface should be soft with a hardness of generally 25-35 (Shore hardness). Too soft or too hard can affect the transfer quality of ink.
2. The requirements for ink transfer on printing rollerss are different from those on rubber blankets. The printing rollers requires a large amount of ink absorption and low ink transfer rate. This can often store more ink on the glue roller, helping to maintain even ink delivery, so that the ink system can be made uniform in a short period of time when the machine starts printing. Due to the adsorption of a large amount of ink on the printing rollers, the ink transfer rate is low, but enough ink can still be transported to the printing plate.
3. Adaptability: It is required that the performance and size of the printing rollers should not decrease under different temperature and humidity conditions. Under low temperature conditions, the printing rollers does not strain hard and maintains good transmission performance. At high temperatures, it is required that the printing rollers is not dry or rotten. During the operation, it is required that the printing rollers generates less heat to keep the ink dry and unchanged.
4. Oil resistance: During printing, a large amount of ink is adsorbed on the surface of the printing rollers. When printing is stopped, the surface of the printing rollers is often washed with fatty hydrocarbon oil, so the oil resistance of the printing rollers is stronger. Rubber rollers with poor oil resistance are prone to expansion or contraction, causing size changes and affecting printing.