| 摘要 |
PURPOSE:To detect a reflectance of a photosensitive drum in good linear properties by an optical sensor, by changing a light emitting output in accordance with a light receiving output. CONSTITUTION:An optical sensor 11 detects the fact that a light from a light emission element reflects on the surface of a photosensitive drum 1 and its reflectance is recognized. By deciding the proper timing for detection, one optical sensor 11 performs two detections whether a toner image density and a transferring paper are stuck onto the drum 1 owing to failure of separation by a separation charging device 8. As a toner and transfer paper are different large in reflectance, a current level of a light emitting element is changed over in accordance with a light receiving output and the level of the light receiving output is adjusted. |
