| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a developing device capable of securing toner replacement performance even at both ends, capable of maintaining toner performance over a long period in the whole image area, and capable of forming a stable image. <P>SOLUTION: The developing device has a developing part with a developer storage chamber, a developer supply chamber and a developing means. The developing device includes an overcharge preventive valve provided with first openings and a second opening arranged an under side thereof, and positioned in a developer storage chamber side with respect to a boundary wall for covering the first opening part and for partitioning the developer storage chamber from the developer supply chamber. The plurality of first opening parts are arrayed along a boundary wall width direction. A volume of a passage route from end openings formed in boundary wall both end edges out of the first openings is larger than a volume of a passage route from the central opening formed between the end openings, when the overcharge preventive valve is opened, as to the volume of the developer passage route with the developer passing from the developer supply chamber to the developer storage chamber, in the developing device. <P>COPYRIGHT: (C)2009,JPO&INPIT |
