ELEKTROTATOGRAPHISCHES KOPIERGERAET

摘要

A photoconductive drum (32) is charged, radiated with a light image of an original document (34) and developed to produce a toner image. The density of the toner image is sensed and additional toner fed to a developing unit (37) if the sensed density is below a predetermined value. The sensed toner density is compensated for variations in charge potential, light image intensity, electrostatic image potential, developing bias voltage, power supply voltage and/or sensor output so as to be independent of these variables.