| 摘要 |
PURPOSE:To prevent a discharging device and a photoreceptor from breaking down and to prevent damages of a driving system without any copy of defective picture quality, by returning stream corona discharge occurring to the corona discharging device to stable glow corona discharge. CONSTITUTION:A discharging wire 19 is electrified over the photoreceptor 1 by glow corona discharge and once stream corona discharge occurs, the current amount of a line 17 increases, which is detected by a monitor device 20 such as an ammeter; and its signal SI is sent to a circuit 21 to be compared and the output value of a high-voltage power source 15 is varied by a current control circuit 23 to reduce the discharging current of the line 17, stopping the stream corona discharge. The surface potential of the photoreceptor, on the other hand, is detected by a potential sensor 26 and compared 21, controlling the moving speed of the photoreceptor 1 by a driving system control circuit 24 so that a set potential is obtained. A noise is monitored on the device 20 instead of the current amount and a noise increase due to abnormal discharge is utilized to detect the abnormal discharge, sending the detection signal to a comparison control circuit 21. |
