| 摘要 |
PURPOSE:To obtain copies of good pictures by stabilizing the potential variation of a photosensitive body. CONSTITUTION:A sensor 26 is arranged in the position following an overall exposure lamp 14 to detect the surface potential of a photosensitive drum after the overall exposure processing. The detected surface potential value is compared with a preliminarily set reference potential value by an operating circuit (CPU)28, and the output of a driving high voltage transformer 29 of dischargers 12 and 13 is corrected in accordance with the difference between them to correct the electrostatic charge quantity, namely, the potential of the photosensitive drum, or outputs of a development bias generating power source 30 and a power source of an illumination lamp 20 are corrected. The bias voltage control to a developing device 15 and the output control of an illuminating lamp power source 2a are performed in the direction where the variation of output pictures due to the potential deviation is compensated. Thus, a short-time or long-time potential variation of a photosensitive body 10 is stabilized or compensated to output always copies of good pictures. |
