| 摘要 |
PROBLEM TO BE SOLVED: To provide a developing apparatus which can produce a high quality image stable by preventing a developer from invading into a space between a developer bearing member and a sealing member without increasing a driving load of the developer bearing member. SOLUTION: A developing apparatus includes a developer container 2 for containing a developer containing magnetic particles, a developer bearing member 10 (developing sleeve 10b) which is rotatively held by the developer container 2, bears and conveys the developer on its surface with a magnetic roller (magnet) 10a arranged therein. In this case, a ring shape magnetic material (first magnetic member) is provided on the circumferential surface of the developing sleeve 10b at both ends, a plate magnetic material (second magnetic member) is provided along at least a part of the circumferential surface of the developing sleeve 10b with a predetermined gap (g) to the periphery of the ring shape magnetic member, a magnetic circuit is formed so as to concentrate magnetic line of force in the gap (g) through the magnetic roller 10a, the plate shape magnetic member and the ring shape magnetic member, and the developer is prevented from leaking out by a magnetic brush of a developer formed along the magnetic line of force. |
