Influence of the surface roughness of the printing form on the relative gear ratio of the friction printing pair

The article investigates the mechanics of a friction printing pair, taking into account the surface roughness of the printing form. The aim of the work is to study the influence of the surface roughness of the printing form on the relative gear ratio. It was found that the deepening of the microprotrusions of the surface roughness of the printing form create additional displacements and deformation of the deckle in the area of the printed contact. A brief review of the literature data on the study of a friction printed pair is given, the analysis of which has shown that the study of the mechanics of a printed pair does not take into account the influence of the microgeometry of the contacting surfaces on the parameters under study. To determine the penetration of surface roughness irregularities, a discrete roughness model is used, presented in the form of a set of identical spherical segments. The study of the influence of microgeometry on the deformation of the deckle also on the relative gear ratio was carried out taking into account the deepening of the micro-protrusions of the surface roughness of the printing form into the body of the deckel, which lead to additional displacements and deformation of the deckel, including. A method was developed for calculating the deformation of the deckle and the relative gear ratio, taking into account the surface roughness of the printing form, and it was found that at large values of the roughness value, the relative gear ratio for elastic deckles decreases, and for compressed ones, it increases. This study, in comparison with analogs, makes it possible to determine the change in the length of the deckle of a given composition with the known parameters of the printed pair, mechanical characteristics and microgeometry of the surface of the printing form. The calculation method allows you to predict the quality of printed impressions, the circulation life of printing plates and to fine-tune the printing press before the printing process.