| 摘要 |
PURPOSE:To easily control the electrostatic charging potential of a drum and to prevent the deterioration of image quality by measuring an electric current which flows in a photosensitive drum and adjusting the voltage of a control electrode so that the correlative deviation between the electric current and the electrostatic charging voltage may be compensated. CONSTITUTION:The charge wire W of a main charger M is disposed facing the surface of the photosensitive drum PC and a grid electrode G is disposed between them, and the wire W and the electrode G are respectively connected with high voltage power sources HM and HG. And an electric current detection circuit Id is connected between the drum PC and an earth. And, the electrostatic charging current of the photosensitive drum PC is detected in the electric current detection circuit Id at a desired timing for measuring the electric current by an I/O controller IOC, and the output voltage of the power source HG is adjusted so as to coincide with a prescribed target value, and the correlation between the output voltage and the electrostatic charging voltage of the photosensitive drum PC is set so that the compensation for the change in temperature and humidity, etc., may be executed. |
