| 摘要 |
PURPOSE:To correctly set a developing bias voltage and to prevent the lowering of picture density by making the responding time constant of a storage circuit when the output potential of a potential detecting means changes from a low level to a high level different from that when the output voltage changes from the high level to the low level. CONSTITUTION:The surface potential of a photosensitive body 1 after exposure is detected by means of a potential detecting means 5 and the output potential of the means 5 is stored in a storage circuit 8. The responding time constant of the circuit 8 when the output potential of the means 5 changes from a low level to a high level is different from that when the output potential changes from the high level to the low level. Then a developing bias voltage applying means 9 applies a developing bias voltage to a developing section 21 in accordance with the storing potential of the circuit 8. Therefore, the developing bias voltage can be set correctly and the lowering of the picture density can be eliminated. |
