Apparatus and method for measuring and maintaining copy quality in an electrophotographic copier

Abstract From the Canadian patent

Factors affecting copy quality are continuously adjusted during copying in accordance with the actual charge on the photoconductor relative to a fixed reference potential. The photoconductor carried on a moving, partially exposed constant, potential conductive support is sensed by a probe. The probe supplies a signal as a function of the potential on portions of the photoconductor and the conductive support passing by the probe. A circuit converts the probe signals into digitized values representing the current photoconductor potential relative to the support. The digitized values adjust copier parameters to compensate for deviations of photoconductor potential from predetermined desired …