| 摘要 |
<P>PROBLEM TO BE SOLVED: To attain high-speed image formation, while maintaining performance, such as image quality, durability, and reduction in size, in a developing device and an image forming apparatus that has three developer transport paths according to separate functions, which are the developer supply, and its recovery and agitation. <P>SOLUTION: The developing device includes a supply transport path 9 having a supply screw 8 for transporting two-component developer, supplying it to a developing roller 5; a recovery transport path 7 having a recovery screw 6 for transporting developer recovered from the surface of the developing roller; and an agitation transport path 10 that receives extra developer from the supply transport path and recovered developer from the recovery transport path, has a screw 11 for agitating and transporting the extra developer and recovered developer, and supplies the agitated developer to the supply transport path. In the developing device, the agitation screw has a screw pitch so as to transport the developer at the downstream end of the agitation transport path and supplies a predetermined amount of developer to the upstream end of the supply transport path. The screw pitch of the supply screw is longer than that of the agitation screw. <P>COPYRIGHT: (C)2008,JPO&INPIT |
