| 摘要 |
PURPOSE:To lessen the run-out of carriers and the adhesion of toners by stepwise lowering the surface potential of an image carrying member to be subjected to photoirradiation down to the developing bias value by a developing means at the time of forming an image by reversal development. CONSTITUTION:The surface potential is lowered to the surface potential VA by the light obtd. by controlling the intensity of the light beam from a first LED optical head, which is thus at the surface potential VH in a time T verses electrostatic charge potential V characteristic diagram, so as to attain the same voltage value as the voltage value applied on a developing tank or slightly higher than the value. The surface of a photosensitive drum 1 is then projected with the light beam at the intensity of the light at which the surface potential drops down to nearly zero V by turning on the bias voltage applied on a developing device 4. Since the developing device 4 is provided downstream of the point to be cast with the light beam, the light intensity is increased slightly earlier by as much as the time required for the photosensitive drum 1 to rotate. The destaticizing stage is ended by irradiating the drum for the time for one turn of the drum after the control to drop the surface potential down to near zero V is started. |
