| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing device configured to prevent a defective image from being generated by toner scattering and developer condensation.SOLUTION: A developing device 3 includes at least an opening for partially exposing a developing sleeve 302 to the outside, and a casing 301 having a toner supply part 309. The developing sleeve 302 has a plurality of magnetic poles for napping developer on the surface. A developer supply member 304 and a developer recovery member 305 arranged vertically in the casing 301 are formed of a conveyance member for conveying the developer. An opening in the casing 301 has an inner wall 301A facing the developing sleeve. In the inner wall 301A, a casing gap equivalent to a facing gap with the developing sleeve is changed from the upstream side 301A1 to the downstream side 301A2 in the moving direction of the developer which enters the opening along with the rotation of the developing sleeve 302, so that the downstream side 301A2 becomes larger from a part SL in the moving direction. |
