The Impact of Top Dot Shapes of the Printing Plate on Dot Formation in Flexography

摘要

The top dot shape is an important element of plate dot geometry which has a significant effect on dot formation on the prints. There are several key parameters that can affect individual dot deformation: nip engagement, line ruling and dot geometry. The main question is how these parameters affect dot deformation. This paper researches the issues regarding print quality in highlights, especially dot formation on print at lighter and higher pressure which leads to inconsistency in the printing process like loss of highlight detail and unpredictable dot gain. The purpose of this research is to improve the understanding of the effect of nip engagement on dot deformation and to determine how top dot shapes affect dot formation. A test image was printed with cyan UV ink on aluminium foil on the pre-printed opaque white ink with plates of different types of top dot shapes, round and flat. The images were taken from the prints and analysed by using ImageJ software. All the important parameters of dot formation including uniformity of density, dot sharpness and dot roundness were evaluated. The results highlight the importance of the top dot shape in plate dot geometry which has a significant effect on print dot formation.