Developing apparatus having magnetic lower limit domain between repulsion magnetic fields

Abstract

When the structure is arranged such that one of the repulsion poles is used as a developer layer thickness regulation pole, screw pitch-shaped density unevenness occurred at the rear end of a solid black image. To provide a developing apparatus, comprising a developing container containing developer including magnetic carrier and non-magnetic toner, a developer bearing body provided at an opening of the developer container, for rotating while bearing the developer, a magnet member provided within the developer bearing body, the magnet member having a first magnetic pole, and a second magnetic pole adjacent on the downstream side of the developer bearing body of the first magnetic pole in a direction of rotation thereof, having a second magnetic pole having the same polarity as the first magnetic pole, a regulating member provided in the vicinity of the second magnetic pole, for regulating an amount of developer on the developer bearing body, in which between the first magnetic pole and the second magnetic pole, there exists 40° or more an area having 8 mT or less in magnetic flux density in the direction of the normal to the surface of the developer bearing body.

Dependencies are inferred from the claim text.