DEVELOPING DEVICE AND IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To excellently eliminate a lower density caused by the failure of a circulation due to so-called packing developer in the vicinity of a developer carrier, with a simple configuration. SOLUTION: A magnetism collecting means for concentrating a still magnetic field generated from a magnetic field generating means 26e is provided in the part nearer to the outside in a radial direction of the surface 26d2 facing the upstream side in the rotational direction of a developer carrier, in the surface of a developer layer thickness regulating member 26d regulating the thickness of the layer of the developer carried on the outer circumferential surface of the developer carrier 26c, to generate a concentrated magnetic field. Thereby, a developer fluid bed in the vicinity of the developer carrier 26c is extended by connecting a developer take-in pole S2 on the upstream side in the rotational direction of the developer carrier 26c and a line of magnetic force, without losing a magnetic force, to perform efficient stirring. Thus, it is made to be hard for an immobile layer to occur. COPYRIGHT: (C)2011,JPO&INPIT