| 摘要 |
PURPOSE:To improve reliability and reduce costs by removing the carrier components on the surface of a rotary sleeve with a film-like member, detecting the amount of the toner remained on said surface, and controlling the concn. of the toner with the detected amount as concn. information. CONSTITUTION:In case a magnet roller 31 for conveying the developer is provided in a dry type developing device performing developing by circulating and conveying the powdered developer consisting of mixed components of toners and carriers, the optical axis of a detector 18 is aligned to the center of the roller 31 on the side of the roller 31 where there is a magnet 8 is absent, and a ''Mylay '' scraper 34 which is a film-like member is touched to the surface 7 of the rotary sleeve at an upper side of substrate 33, and the toner a'' remained on the surface of the sleeve 7 is detected with the detector 18 irrespectively of whether during rotating or stoppage. |
