| 摘要 |
PURPOSE:To stabilize image density and obtain a good image by placing upper and lower developer carrying means off from a developing sleeve and preventing direct contact with developer held by the developing sleeve. CONSTITUTION:Developer for replenishing is supplied to a lower screw 4 and charged sufficiently, and then, supplied between a sleeve 3 and an upper screw 4. Developer 10 participated in developing is carried again to a developing device by rotation of the sleeve 3, scraped off by a scraper 6 and carried to an area C by the lower screw 4 which is at a position off from the sleeve 3. The developer mixed by the screw and made to prescribed toner concentration is carried to the upper part of the developing sleeve 3. In this constitution, by providing upper and lower screws 4', 4 off from the sleeve 3, movement of developer held by the sleeve 3 is not disturbed, and unevenness of concentration in axial direction of the sleeve 3 and traces of screw pitch etc. can be eliminated perfectly, and initial picture quality can be maintained for a long term.
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