DEVELOPING DEVICE AND IMAGE FORMING DEVICE

PROBLEM TO BE SOLVED: To fully mix a developing agent containing toner and carrier without using a larger developing device and to use the supplied and appropriately charged toner for development. SOLUTION: In the developing device 20, the developing agent D containing the toner and the carrier guided out of a guide port 25a provided downstream in the conveyance direction of a developing agent conveyance supply part 22 which stirs, conveys and supplies the developing agent D to a developing agent carrier 21 is sequentially guided to a plurality of developing agent conveyance parts 26a-26c through each guide port 25b, 25c for stirring and conveying and is returned upstream in the conveyance direction of the developing agent at the developing agent conveyance supply part from the guide port 25d of the last developing agent conveyance part 26c. The developing device 20 has a portion where the developing agent is guided through the guide port by the force of gravity and a portion where the developing agent is guided through the guide port against the force of gravity, and the length of at least some of the developing agent conveyance parts other than the last developing agent conveyance part is reduced. COPYRIGHT: (C)2010,JPO&INPIT