| 摘要 |
PURPOSE:To form an image of a uniform image density by detecting fluctuations in the level of dark decay on a photosensitive drum and compensating the fluctuations in the level of the dark decay in the vicinity of a developing means. CONSTITUTION:A change in a surface potential along a peripheral direction on a photosensitive body film 12 is detected as the change of the attitude of a detector 40. Then, a light receiving signal inputted from a light receiver 42 is compared with an initial light receiving signal corresponding to an initial attitude in a comparator 27 and a signal corresponding to the change width of the light receiving signal is read out by a controller 28. The controller 28 reads data corresponding to the fluctuation width from a memory 29 and adjusts a potential adjusting part 51, to change the grid current Igc or grid potential Vg of a grid 23. Further, the controller 28 holds the grid current Igc or grid potential Vg at the adjusted value, until a condition for adjusting the grid current Igc or the grid potential Vg is satisfied, by using the potential adjusting part 51. |
