Influences of the photopolymer plate on print quality in UV flexographic printing

Abstract

This thesis studies the effect of UV flexographic inks on photopolymer plate physical characteristics and how these changing characteristics affect the print quality. Using six photopolymer plates, two UV inks, and three printing substrates, thirty-six case studies of the combinations of the materials were made and tested for their stability, compatibility, and print quality. The hardness, thickness, and weight of the photopolymer plate were measured, to analyze the changes in plate physical characteristics. The print quality was evaluated using tone reproduction curves, and visual assessment. The results imply that each material combination has a unique quality: namely, the Nyloflex Sprint has the most resistance against radical UV ink, the Nyloflex FAH performs an equal stability for both radical and cationic inks, and the Nyloflex ACE, which could produce a high quality print, can be considered not suitable for a long-run job. In addition, factors determining the degree and extent of swelling were listed and a consideration about a relationship between plate swelling and print quality was discussed.