| 摘要 |
PURPOSE:To compactly incorporate a detecting member detecting the quantity of a developer in a position where a developer surface as the subject of detection is near. CONSTITUTION:The image forming device is constituted so that a part corresponding to the nonimage region of a guiding member 4b guiding the carrying direction of a belt photosensitive body 1 is notched, to embed a photocoupler PC1 composed of a light emitting element PC1A and a light receiving element PC1B, an infrared ray projected from the light emitting element PC1A passes a translucent belt photosensitive body 1, is reflected by the periphery of a developing sleeve 9A and then, passes the belt photosensitive body 1 again, to be made incident on the light receiving element PC1B, and the ratio of the component of toner in a developer carried on the periphery of the developing sleeve 9A is detected by a change in the reflectance of the infrared ray. |
