| 摘要 |
PURPOSE:To detect the presence of an obstacle, such as the stain, flaw, and due of an optical system or a photosensitive body, dust in the air, and a scattering. CONSTITUTION:A drum earth current detection part 12 is provided in an earth cable of a photosensitive drum 9. By comparing a drum earth current signal detected by the detection part 12 with an image signal or a drive signal of a light emitting element, missing of a pixel by an obstacle is detected. An operator is informed of this. |
