Patent ID: 8147026
Filing Date: 2012-04-03
Classification: B41J

Abstract:
1. A method of matching the optical density of prints produced on a print engine assembly including a first and a second print engine, one of which is an inkjet print engine, comprising: providing the first and second print engines, each including a respective densitometer; measuring the transmission density of a known filter with the densitometer of the first print engine to provide a first output voltage; measuring the transmission density of the known filter with the densitometer of the second print engine to provide a second output voltage; comparing the first and second output voltages; based on the comparison, compensating the output voltage from the densitometer in the first print engine for the output voltage for the densitometer in the second print engine; sensing the optical density of a first image area of a first image produced by the first print engine using the densitometer in the first print engine after the compensation step; sensing the optical density of a second image area of a second image produced by the inkjet print engine using the densitometer in the second print engine after the compensation step; comparing the sensed optical densities of the first image area and the second image area and determining if they are substantially equal; and if the optical density difference is greater than 0.03 then adjusting one or more set points on the inkjet print engine until the optical densities of the first image area and the second image area differ by less than 0.03.