| 摘要 |
PURPOSE:To suppress the degradation of electrostatic charging performance and to excellently maintain image quality by providing a carrying part for replenishment fetching the carrier developer of a developer replenishing part in a developing tank and a carrying part for discharging a developer in a developing tank and driving these carrying parts with the same means. CONSTITUTION:Projecting parts 16b and 16c are formed in the parts of the developing tank 16 corresponding to both end parts of a developer replenishing/discharging shaft 22, the replenishing screw 22a as the carrying part for replenishing is formed on one end part of the developer replenishing/discharging shaft 22 and the discharge screw 22b as the carrying part for discharging is formed on the other end part, so that the developer is carried in the direction of A by the rotation of the developer replenishing/discharging shaft 22 and the degraded carrier in the developing tank 16 is exchanged with a fresh carrier. Since the developer is replenished/discharged by a quantity corresponding to the drive of the carrying part for replenishing 22a and the carrying part for discharging 22b by the developer replenishing/discharging shaft 22, even if the quantity of the developer in the developing tank 16 is fluctuated, the developer is surely discharged to exchange the developer in the developing tank 16. Thus, the ratio of the exchange of the degraded developer for the fresh developer can be controlled. |
