Charge density control

Abstract From the Canadian patent

Abstract, An electrophotographic copier having a toner concentration control apparatus which periodically effects a toner-patch test cycle during which the optical density of toner deposited on a photoconductor test area is measured as by, light reflectance. A time period of copier non-use exceeding a preset time period, or a copier on/off operation, referred to as critical events results in a, transient mode of copier operation which includes reduction of photoconductor charge magnitude during the next subsequent use, independent of the extent of the prior copier use history. During such subsequent use the, toner-patch test cycle is operable to effect closed-loop control of changing the …