| 摘要 |
PURPOSE:To maintain the surface potential of a photoreceptor at an appropriate value in a short time, by feeding electric change onto the photoreceptor by changing the output in steps with an electrifier while the photoreceptor is rotated for a fixed angle and detecting a point where the surface potential of the photoreceptor coincides with a reference potential. CONSTITUTION:A pattern signal 25 is outputted in accordance with a pattern control signal 16 outputted from a control circuit 13 at a fixed timing, and electric charge is fed to a photoreceptor 1 from an electrifier 2 in accordance with a signal proportional to the pattern signal 25 from a variable high voltage generator 18. The output of the electrifier 2 is changed in steps by a pattern generaror 14 and the variable high voltage generator 18 and the surface electric charge of the photoreceptor 1 is detected by a measuring means 11. When a surface potential signal 27 coincides with a reference signal 28, a coincidence signal 29 is outputted and fed back to a change-over circuit 15, and, after this, electric charge is fed to the photoreceptor 1 with this voltage. Therefore, it is not necessary to repeatedly approach the surface potential to a target value and stable surface potential control can be performed quickly. |
