| 摘要 |
PURPOSE:To control exposure quickly by providing an automatic exposure control mechanism which provides prescribed surface potential with respect to a prescribed density. CONSTITUTION:Potential is detected by a sensor 7 between a full surface exposure lamp 4 and a developing electrode 5, and the output of a high voltage transformer 9 is regulated. Next, the exposure of a lamp 11 irradiating a standard white plate 10 other than an image area is continuously lowered. The reflected light of that time is conducted onto a photoreceptor 1 via mirrors 12, 13 thereby exposing the photoreceptor. The standard white potential on the photoreceptor is detected with the sensor 7 and when the potential attains a target value, a signal for stopping the change of the quantity of light is emitted to the lighting control circuit 14 of the lamp 11 from a control circuit 8. The circuit 14 stores the exposure of the stopping time, and when a copy signal goes on,the lamp 11 is lighted at that stored exposure. |
