Analysis of vibration of printing unit of offset printing press

There are several causes of vibration of off set printing presses. Major are cyclic work of feeders and deliveries, gaps with mechanisms for fixing plate and blanket in cylinders of printing pair and inappropriate stress between those cylinders. All mentioned above causes increased exploitation of bearings, gears driving cylinders and other parts of the printing press. The consequences of vibration are also breaking of paper web and such artefacts as doubling and streaking on the prints. In this paper printing pair cylinders of lithographic printing press are described as a two-degree of freedom model. Solution of a system of differential equations, which describes this model shows influence of vibration of printing unit cylinders on the fluctuation of the ink film thickness on the prints (magnitude of streaking phenomenon).