| 摘要 |
PURPOSE:To suitably perform the destaticization of a photo-sensitive drum and to prevent conducting the deterioration of the photosensitive drum and the lowering of image quality. CONSTITUTION:A pre-exposure lamp (destaticization means) 11, a primary electrostatic charger 5, a surface potential sensor 21, developing device 7 (7Y, 7C, 7M and 7BK), etc., are disposed along the rotation direction (direction of arrow R1) of the photosensitive drum 3. By the output of the sensor 21, the dark decay quantity of the photosensitive drum 3 corresponding to the disposition position of the respective developing devices 7 is seeked. By the dark decay quantity a destaticization control means 20 adjusts the exposure of the pre-exposure lamp 11. Thus suitable destaticization is performed with the respective developing devices 7 and the accumulation of electric charge caused by little destaticization and the deterioration of the photosensitive drum 3 caused by excessive destaticization. |
