Patent ID: 8068771
Filing Date: 2011-11-29
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a photoreceptor drum including a photosensitive layer; and, a developing roller for supplying a dual-component developer to the photoreceptor drum, characterized in that: the developing roller includes a main magnetic pole for forming a magnetic brush that rubs and supplies the dual-component developer over the photoreceptor drum; the photoreceptor drum includes an opposing magnetic pole having a polarity that is dissimilar from that of the main magnetic pole, located at a position opposing the main magnetic pole across the photosensitive layer; the main magnetic pole is disposed away to the downstream side with respect to the rotational direction of the developing roller from the closest position where the distance between the developing roller and the photoreceptor drum is shortest while the opposing magnetic pole is disposed away to the upstream side with respect to the rotational direction of the developing roller from the closest position of the developing roller and the photoreceptor drum; and the magnetic flux density of the magnetic field formed by the opposing magnetic pole on the center surface of the opposing magnetic pole falls within the range of 15% to 35% of the magnetic flux density of the magnetic field formed by the main magnetic pole on the center surface of the main magnetic pole.