Patent ID: 8100499
Filing Date: 2012-01-24
Classification: B41J

Abstract:
1. A method of detecting print head roll in an ink jet printing system including one or more print heads, the method comprising: forming a test pattern on an image receiving surface using each nozzle from two different rows of nozzles of one print head, the test pattern comprising a plurality of marks arrayed across the image receiving surface in a cross-process direction, each mark in the plurality being formed by a different nozzle of the one print head; detecting the cross-process direction positions of each mark in the plurality of marks; determining cross-process direction spacings between marks in the test pattern based on the detected cross-process direction positions; determining differences between the determined cross-process direction spacings and expected cross-process direction spacings for the marks in the test pattern; correlating the determined differences between the cross-process direction spacings and the expected spacings to a print head roll value for the print head; modifying the print head roll value based on lateral motion of the image receiving surface prior to adjusting the physical position of the print head; and adjusting a physical position of the print head based on the modified print head roll value.