| 摘要 |
PROBLEM TO BE SOLVED: To stabilize toner concentration by making the circulation action of developer inside a developer storing part more actively in a developing device taking toner by the moving of the developer without the use of a toner concentration detecting means. SOLUTION: As to this developing device 2 which is provided with a developing sleeve 4 incorporating a magnet roller, holding and carrying two-component developer on its surface, a doctor 6 controlling the amount of the developer on the developing sleeve, the developer storing part storing the developer scraped by the doctor, a second control member 7a disposed on an upstream side in the carrying direction of the developer in the developer storing part from the doctor, and a toner hopper having a toner supply aperture part 8a supplying the toner to the developing sleeve, and which changes a condition that the developer on the developing sleeve takes toner by changing the contacting condition of the developer and the toner by the change of the toner concentration of the developer on the developing sleeve; magnetic poles P4 and P5 having the same polarity are arranged on the upstream side in the developer carrying direction from the magnetic pole P1 of the magnet roller opposite to a photoreceptor and on a downstream side from a position opposite to the toner supply aperture part. |
