Patent ID: 7899372
Filing Date: 2011-03-01
Classification: G03G

Abstract:
1. A developing device for developing an electrostatic latent image carried on an electrostatic latent image bearing member that is rotating in a first rotational direction so that a peripheral surface thereof is moving in a first linear direction, the developing device comprising: a developer bearing member having a substantially cylindrical shape and configured to be positioned adjacent to the electrostatic latent image bearing member and that rotates in the first rotational direction so that a peripheral surface of the developer bearing member adjacent to the surface of the electrostatic latent image bearing member is moving in a second linear direction which is opposite to the first linear direction, the peripheral surface bearing developer and feeding the developer to the electrostatic latent image bearing member at a developing region in which the developer bearing member faces the electrostatic latent image bearing member; a magnetic field generating member unrotatably placed inside the developer bearing member and having a plurality of magnetic poles including a main magnetic pole positioned in the vicinity of the developing region; a layer thickness restricting member configured to restrict a layer thickness of the developer on the peripheral surface of the developer bearing member at a position upstream of the developing region in the second linear direction; and a spike-height restricting member having a tip located upstream of a proximal position in the second linear direction, the proximal position being a position at which the electrostatic latent image bearing member and the developer bearing member are located closest to each other, the tip also being located downstream in the second linear direction of a first circumferential position on the peripheral surface of the developer bearing member at which an intensity of a magnetic field generated by the main magnetic pole assumes a half of the maximum value in the radial direction of the developer bearing member, the spike-height restricting member restricting a height of spikes of the developer on the peripheral surface of the developer bearing member which are caused by a magnetic field generated by the main magnetic pole.