| 摘要 |
PURPOSE:To provide a developer layer thickness detecting device capable of detecting the layer thickness of a developer with high accuracy. CONSTITUTION:A developer layer thickness detecting device is provided with a developing sleeve 22 at least one longitudinal part of which is formed of a transparent member; a light projecting means 51 disposed either inside or outside the developing sleeve 22 so as to inject light toward the transparent part 42 of the developing sleeve 22; and a light receiving means 52 disposed opposedly to the light projecting means 51, either inside or outside the developing sleeve 22, that is, on the opposite side to the light projecting means 51, so as to receive the light emitted from the light projecting means 51 and transmitted through the transparent part 42 of the developing sleeve 22. The developer layer thickness detecting means then detects the developer layer thickness on the basis of the detection output of the light receiving means 52. |
