| 摘要 |
PURPOSE:To prevent reiterative detection by the same developer by detecting the concn. of a toner and recovering the toner used for the detection into a developer hopper in recovering the used toner into the developer hopper above a developing sleeve by means of scooping up rollers. CONSTITUTION:The developer is supplied from a developer hopper 3 to a developing sleeve positioned below the same, and the developer used for developing is scraped off from the sleeve by a scraper 8 via sccoping up rollers 6, 7, and is recovered into the developer hopper. A toner concn. detector 10 is provided at the mid-point of the scraper, and a partition plate 4b is so constituted that the developer past this detector is also recovered into the developer hopper. In the case of providing a detector on the outside of the partition plate, it is equally well to recover the developer into the hoper by providng a trough or the like for conducting the developer to below the detector. |
