| 摘要 |
PURPOSE:To realize the real time control of an exposure control system and to reproduce a highly accurate image in accordance with high speed copying by estimating a dark attenuating quantity after a fixed time elapses based on the surface potential of a photosensitive drum. CONSTITUTION:In an exposure control circuit 30 having correction information derived from functional relation between a current value flowing in the surface of the photosensitive body 1 at the time of electrostatic charging and the dark attenuating quantity of the surface potential of the drum at a developing part; the duty of a pulse width modulation signal obtained by comparing the detected value of the surface potential of the drum 1 by a secondary side scorotron 11 with reference voltage is contrasted with the correction information, and the output voltage of an exposure lamp power source circuit 29 is corrected corresponding to a correction value obtained by the contrast, then the light quantity of an exposure lamp 27 is controlled. |
