The elimination of vertical partial ghosting in offset press

A PZ2720-01 four-color two-color offset press has recently experienced partial vertical ghosting failures when printing senior two-tone coated text and line products.

Problems like this occur before, and most of the problems occur on the cavities of the first impression cylinder, with dead teeth or loose teeth. Most of the causes of such failures are caused by residual chemical agents and paper fibers during the cleaning of the impression cylinder, resulting in inflexible tooth decay.

Ghosting appears on the side of the pull gauge, and the ghosting from the cornice to the end of the paper gradually becomes serious, especially in the middle of the “Shi” line. The fault should be on the impression roller on the side of the pull tab or on the tusks of the intermediate transfer drum. After careful inspection and adjustment, the failure of trial and error ghosting has not been ruled out. The car accidentally found out that there were two tooth holders with paper powder on one side of the pull tab, and the other tooth bases were very bright. After testing, the paper strips were placed in the tusks, and they were pulled out. Adjust and correct the elasticity of teeth and troubleshoot.

Failure analysis: Because it is time to print positive four pages of paper, instead of using tooth decay often enters Tangshan Yuyin, easily causing inflexible teeth, when a transfer roller passes to an impression roller of double diameter, The drum could not be smoothly transferred, causing longitudinal partial ghosting failure.