Impact Of Screen Ruling on the Formation of the Printing Elements on the Flexographic Printing Plate

Flexography is a printing technique widely used in the packaging production. The main feature of the flexography is the usage of the printing plate which is elastically deformed during the reproduction process. The printing plate is made of elastic material, rubber or nowadays mainly of different types of photopolymer. Elasticity of the plate enables printing on a wide range of printing substrates (papers, foils, board, magazines, hygienic papers etc.), which is one of its advantages compared to other printing techniques. On the other hand, deformations of the printing plate in the printing process caused by the pressure between the printing plate and substrate present major limitation of the flexography. Beside functional properties of the printing plate in the printing process, the plate making process including photopolymerization highly influences the value of the halftones on the printing plate, and consequently on the final product. The aim of this paper is to examine the influence of the screen ruling on the formation of the printing elements and the procedure of the printing plate making process adjustment in order to achieve optimal quality of the printing plate and, therefore, the final product.Results have shown that the usage of different screen ruling is of great significance in processes of printing plate curve adjustment. It was proven that the usage of different screen ruling highly influences the relief depth and a cross-section of the printing elements (3D analysis), which have a significant impact on the final product quality, but cannot be detected in 2D analysis.