Patent Document ID: 9278566
Application ID: 14586931
Patent Status: 1

Claim One:
1. A process for measuring and correcting the amount of mis-registration between first and second print heads of a digital printing machine without physical adjustment of the first and second print heads, the process comprising the steps of: (a) printing a calibration test page comprising a plurality of pairs of overlapping registration marks created by the first and second print heads; each of said pair of overlapping registration marks comprise a target region comprising X and Y co-ordinates; (b) scanning the calibration test page to produce a bitmap image; (c) processing said bitmap image to produce a mis-registration score for each of the target regions; said step of processing said bitmap image comprising the steps of: blurring the bit map image to produce a blurred bit map image; thresholding the blurred bitmap image to produce a binary black and white image; and selecting the target region within the binary black and white image having the least amount of black pixels as a selected target region indicative of the least amount of moire patterns and the best mis-registration score; (d) producing X and Y coordinate registration correction amounts corresponding to the co-ordinates of the selected target region; (e) adjusting the print data based upon the X and Y coordinate registration correction amounts to produce adjusted print data; and (f) sending the adjusted print data to the second print head.