Effect of roll patterns on the Ink transfer in R2R printing process

Abstract

Ink transfer process from the printing roller to the web was investigated using a CFD technique for the roll-to-roll printing applications. A parametric study was conducted to identify the effects of roll pattern geometry on the ink transfer process. In order to make the present analysis more relevant to the real printing system, 3-D computational configuration was set up using the information obtained from the typical roll-to-roll system. Simplified one-dimensional semi-analytic analysis based on Reynolds equation was also conducted in order to assess the validity of the 3-D CFD results. Pressure information suggests that even a simplified 1-D analysis is reasonably good in capturing the relevant flow physics. 3-D simulation shows that the quality of the ink transfer process is very sensitive to the width of the roll patterns. This sensitivity is believed to be due to the relative importance of surface tension over any other force modes under the 100 micrometer range.