An Investigation of Press Response Time Due to Inking Change on a Web Offset Press

This paper describes an innovative method of using x-bar and R charts to investigate the response time of a web offset press when inking changes are made. Initially, a test form with two identical halves was printed uniformly across the width of the web. Then two levels of inking changes were made on either side of the test form. Density measurements on solid ink patches were collected and analyzed for the transitional phase, i.e., from before the inking change was introduced to after another inking equilibrium was shown on sampled press sheets. Additionally, colorimetric measurements on three-color overprint tints were collected and analyzed from sample press sheets. It was concluded that the press response time is inverse proportional to the amount of inking changes made.