| 摘要 |
PURPOSE:To easily and accurately obtain the specific electrostatic charging potential of an before-exposure part more than when the thickness of a photosensitive layer is used as a reference and to obtain an image of superior picture quality by using electrostatic charging ability as the reference. CONSTITUTION:A photosensitive body 1 which rotates as shown by an arrow is corona- charged with a specific applied voltage of, for example, 6.8kV by an electrostatic charger 2. Its electrostatic charging potential Vs is measured by a potential probe 3 at a position corresponding to the before-exposure part of a copying machine and the current ISe conducting to the photosensitive body at this time is detected by a sensor 5, thereby knowing the electrostatic charging ability ISe/Vs of the photosensitive body. The electrostatic charging potential of before-exposure part of an electronic photographic device and the electrostatic charging ability of the photosensitive body have high correlation. For the purpose, the electrostatic charging potential of the photosensitive body is adjusted more easily to a specific potential by setting the output of the high voltage power source based on the charging ability of the photosensitive body which is measured and evaluated previously than by adjusting the output of the high voltage power source based on the film thickness of the photosensitive body.
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