A densitometer for measuring marking particle density on a photoreceptor having a compensation ratio which adjusts for changing environmental conditions and variability between machines

摘要

An electrographic apparatus having a densitometer, which achieves improved measuring of marking particle density on a photoreceptor or the like. The measuring method detects both specular and diffuse light reflected off of the photoreceptor containing marking particles. A compensation ratio is generated from a high density marking particle patch, and is used to compensate the marking particle density to both changing environmental conditions and differences between individual machines. Thus, a more accurate specular signal is calculated which is an accurate indicator of toner density of mass per unit of area concentration. These concentration measures enable accurate adjustments of the electrographic apparatus color toner development systems.