IMAGE FORMING DEVICE BY REVERSAL DEVELOPMENT SYSTEM

摘要

PURPOSE:To prevent the adhesion of a carrier onto a photosensitive drum and the wasteful adhesion and consumption of a toner at the start and end of an image forming operation. CONSTITUTION:A developing bias voltage is impressed to an electrification region before this region arrives at a position b where the surface of the rotating photosensitive drum 10 faces a developing sleeve 16 in order to prevent the adhesion of the carrier at the time of starting the image forming operation. The rotation of the developing sleeve 16 is started after the electrification region arrives at the above-mentioned position in order to prevent the consumption of the toner. The rotation of the developing sleeve 16 is stopped while the electrification region exists in the above-mentioned position and the impression of the developing bias voltage is stopped after the passage of the electrification region in the same manner at the end time.