| 摘要 |
PURPOSE:To accomplish the fixed control of toner concn. without depending on the reflection of a photosensitive body and to improve image quality by detecting average reflected light during one rotation of the photosensitive body in a state where the rotation of a developing sleeve is stopped by a ground part reflected light detection means. CONSTITUTION:In the state where the photosensitive drum 24 is rotated and the rotation of the developing sleeve 37 of a developing unit 26 is stopped, an image processing part 12 causes a photosensor to detect the reflected light from the ground part of the drum 24, so that the reflected light from the ground part averaged concerning nearly one rotation of the drum 24 is detected as an accurate and stable value regardless of the scratch of the surface or the unevenness of the application of a photosensitive agent, and the fixed control of toner concn. is performed to improve the image quality. Since the detection is performed in a state development is stopped, unnecessary toner does not adhere to the photosensitive body and an effect on the control of concn. is evaded, then the life of developer is prolonged as a system. |
