Patent ID: 7382993
Filing Date: 2008-06-03
Classification: G03G

Abstract:
1. A document processing system comprising: marking engines which each prints a series of control patches of various area coverage, each marking engine having at least one actuator; first and second patch sensors which each measures black tone area coverage voltage value from each control patch printed with a respective first or second marking engine; a relative reflectance determining algorithm which determines relative reflectance values of each respective control patch printed with the first and second marking engines; an engine error determining algorithm which determines (a) a first marking engine relative reflectance error value based at least on the determined first engine relative reflectance value of each control patch and a corresponding first engine target relative reflectance value, and (b) a second marking engine relative reflectance error based at least on the determined second engine relative reflectance value of each control patch and a corresponding second engine target relative reflectance value; and an adjusting algorithm which adjusts at least the relative reflectance target of at least one of the first and second marking engine based at least on one of the first and second engine relative reflectance error value to improve image quality control of the document processing system.