DEVELOPING ROLLER AND DEVELOPING DEVICE

摘要

PROBLEM TO BE SOLVED: To prevent deterioration of a developer without imposing a heavy load thereon by using a specified developing roller and forming a uniform thin developer layer by the action of magnetic poles provided on the surface of the developing roller without using a laminating blade. SOLUTION: Developer is stirred and carried by screw augers 23 and 24 and circularly moves in two developer stirring and carrying chambers. A developing roller 7 has a shaft integrated structure where a main body and a shaft 8a are integrally formed of manganese-aluminum alloy and the shaft 8a is rotatably supported. S poles and N poles are alternately arranged at intervals of 25 to 250μm along the periphery on the surface of the roller 7. When the developer 5 is supplied to the roller 7, one layer of carrier with electrically attracted toner is attached on its peripheral surface due to the magnetic field of a roller surface layer, so that a thin developer layer is formed without using a laminating blade. The developer layer is carried to an area opposed to an image forming body by the rotation of the roller 7 to be used for developing an electrostatic latent image.