Evaluation of Pressures in Flexographic Printing

One of the advantages of the flexographic process is its ability to print at low pressures. This paper presents an evaluation of the impact of pressure changes on the print quality. Experimental data was collected using a commercial central impression printing press. The impact of pressure changes between the anilox chamber, printing plate and central impression cylinder on the print quality were assessed using orthogonal array techniques. The impact of each of the parameters and the interactions between them were evaluated using ink density and tonal reproduction, for a range of line rulings. The results showed the effects could be separated into those affecting the solid density (global ink transfer) and those affecting the tonal reproduction (relative ink transfer). The anilox to ink chamber was shown to affect the density most significantly, while it was the plate to impression pressure that affected the tonal reproduction the greatest.