| 摘要 |
PURPOSE:To stabilize image density by variably constituting the changed potential of an electrostatic charging means for charging the surface of a photosensitive body and increasing the charged potential of the photosensitive body in accordance with the increase of leaked light generated at the time of closing a liquid crystal optical shutter. CONSTITUTION:The charged potential of a photosensitive drum 1 is varied to Vx by shorting resistors Ra-Rc to control the charged potential. The setting of a tap and the setting of the Vx are determined in accordance with the leaked light of the liquid crystal shutter. Namely, the transmitted light of the liquid crystal shutter is controlled by adjusting the light quantity of a light source at the time of opening the shutter, but the optical output of the shutter is changed in accordance with the dispersion of the leaked light generated at the time of closing the shutter. At the time of large quantity of leaked light, the initial charged potential is set to a high level by considering attenuation based upon the leaked light, and in case of small quantity of leaked light, the initial charged potential is set to a low potential VOB in accordance with the reduction of the leaked light.
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