| 摘要 |
PURPOSE: To effectively avert the trouble accompanying the build-up of a developer at the ends of a developer carrying member even if plural developing magnetic poles are arranged from the position of a developer layer thickness regulating member to the end of an effective development region and the pitch between magnetic poles is narrowed. CONSTITUTION: The developer carrying member 1 of this developing device is composed of a rotatable nonmagnetic sleeve 2 and a magnet member 3 which is fixedly installed in this sleeve 2 and is arranged with the plural magnetic poles 6 along the rotating direction of the sleeve 2. The developing device develops the electrostatic latent image formed on a latent image carrying member 4 by the two-component developer G regulated in the layer thickness by the layer thickness regulating member 5 within a range of the effective development region m of the developer carrying member 1 facing the latent image carrying member 4. At least one of the magnetic poles 6 existing in the range from the position of the layer thickness regulating member 5 to the end of the effective development region m of the developer carrying member 1 is formed as the excessive size magnetic pole 6a which is larger than the permissible development width d of the developer carrying member 1 and of which the ends are arranged to project outward from both end positions of the permissible development width d. |
