| 摘要 |
PURPOSE:To reduce toner consumption and to obtain excellent picture quality at low cost with lightweight constitution by stopping developing operation while the part of a photosensitive body which need not be charged electrostatically owing to the difference in arrangement position between an electrostatic charging electrode and a transfer electrode passes through a development position. CONSTITUTION:The electrostatic charging electrode 2 and transfer electrode 6 are connected to a power source 18 in parallel and turned on and off with the same switch 20. At the time of a start button 20 is turned on, the power source 18 is turned on at time t1 and the photosensitive body 1 is held at a voltage V1 and then at a voltage V2 at time t2 which is a specific time later by the overlap charging of the electrodes 2 and 6, thereby forming an image. The part of the photosensitive body corresponding to the time T1 from the time t1 at the time of the photosensitive surface is at an electrostatic charging position 2a to the time when the front end part of the image reaches the development position 5a and the time T2 from the time when the rear end part of image exposure is at the position 5a of the time when the charging position of the photosensitive body reaches the development position is regarded as the part which need not be charged electrostatically to stop the developing operation. Consequently, the toner attraction from a developing roller 5b to the photosensitive body is stopped to reduce the toner consumption, thereby obtaining excellent picture quality. |
