| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing unit that allows an old developer to be prevented from being left behind in a developing unit without relying on a system velocity.SOLUTION: A developer unit 8 comprises: conveyance paths FP1 and FP2 that communicate with each other via two pieces of openings TH1 and TH2; a conveyance path FP3 that communicates with the conveyance path FP1 in the vicinity of the opening TH2, and has a discharge port 85 provided; conveyance members 87 and 811 that convey a developer of the conveyance paths FP1 and FP2 in a first direction and in a second direction; and a developing roller 86 that carries the developer to be conveyed through the conveyance path FP1 or the conveyance path FP2. The conveyance member 87 includes a screw 89 that gives the developer of the conveyance path FP1 propulsion to the first direction, and a screw 810 that gives the developer of the conveyance path FP3 force toward an opposite direction of the first direction, and in a shaft 88, a diameter of at least a part of a first segment P1 where there is no screw provided in the vicinity of the opening TH2 is larger than that of other segments.SELECTED DRAWING: Figure 3 |
