Offset printing fault causes and exclusion

In the offset printing process, there are often missing edition failures, and some operators are indiscriminate, and all of them push the responsibility to the printing process, and they have to use the phrase “unable to print” to avoid further investigation. Off-board failures do have a close relationship with the printing plate, such as poor printing plate, insufficient vacuum, and excessive exposure time. However, the printing plate is not the only cause of failure, and the printing process cannot be ignored. The author summarizes the main causes and exclusion methods of the off-page failure caused by the printing process.

1. The fountain solution is too acidic and the plate image is corroded. Remedy: Increase the proportion of water in the fountain solution.
2. The printing pressure is too large or the lining is too thick and hard to damage the printing plate. Remedy: Reduce printing pressure or replace suitable pad.
3. The pressure of the water roller or ink roller is too large. Remedy: Reduce the pressure.
4. The water glue on the water roller wears and the friction between the plate and the plate increases. Remedy: Replace the glue.
5. The ink roller surface is hardened, loses its elasticity, and the friction force between the plate and the printing plate increases, or the unevenness of the two ends is caused due to the damage of the ink roller, resulting in a significant speed difference at both ends. Remedy: Replace the ink roller.
6. The surface of the blanket hardens. Remedy: Replace the blanket.
7. Toner, paper and Other impurities too much. Remedy: Clean the plate and blanket.
8. The ink is too viscous, and the peel force caused by the printing pressure is too large, even if it is out of print. Remedy: Add repelant or 6# ink to reduce ink viscosity.

(Mao Ming Leyi Computer Paper Printing Co., Ltd. Wu Guoyong)

Source "Printing Technology"