Patent ID: 6065400
Filing Date: 2000-05-23
Classification: B41F,Y10S

Abstract:
In a printer in which at least two printing stations cause images to be printed on a substrate, said printer being capable of registration adjustment, method for monitoring registration of images printed thereby, the method comprising:(a) printing a pattern of spaced black registration marks onto said substrate by operation of one of said printing stations;(b) printing a pattern of spaced non-black registration marks onto said substrate by operation of a second of said printing stations, said pattern of spaced non-black registration marks being superimposed on said pattern of spaced black registration marks to form a composite pattern of registration marks and interposed spaces;(c) illuminating said composite pattern with at least one LED having an output wavelength complementary to said non-black color;(d) examining the reflectivity of said composite pattern at wavelengths complementary to said non-black color to obtain a reflectivity signature for said composite pattern; and(e) comparing said reflectivity signature to a pre-determined reflectivity signature for said composite pattern, indicative of good registration, to determine an adjustment factor for said printer.