Abstract: A developing apparatus, a process cartridge and an electrophotographic image forming apparatus which can obtain a good image, and an end portion regulating member provided in them. The end portion regulating members for regulating the layer thickness of developer passed through interstices between a developing blade for forming a layer of the developer having a predetermined thickness on the surface of a developing roller and magnetic seals provided on the longitudinally opposite end portions of the developing roller in opposed relationship with the surface of the developing roller is provided downstream of the developing blade with respect to the rotating direction of the developing roller.

Abstract: A developing frame which can improve a sealing property for developer at the end portion of a developing roller.

Abstract: A developing device for developing an electrostatic latent image formed on an electrophotographic photoreceptor includes a hollow developing roller, a support member inserted in the hollow developing roller to support the developing roller, a flange member having a first engaging portion engaging with an outer surface of the support member and a second engaging portion engaging with an inner surface of the developing roller, and a gap-holding member disposed at one end of the developing roller, the gap-holding member having an abutment abutting against the electrophotographic photoreceptor for maintaining a gap between the developing roller and the electrophotographic photoreceptor. The abutment overlaps with the second engaging portion in the longitudinal direction of the developing roller.

Abstract: A part (18c) according to the invention has a plurality of abutment portions (71a, 71b and 71c) which come into abutment with an upper-side part in a guide (76) and support the upper-side part, and a plurality of receiving portions (72a, 72b and 72c) with which a plurality of abutment portions provided on a lower-side part in the guide are brought into abutment. The center of gravity of the part is disposed inside a region surrounded by the plurality of abutment portions. Accordingly, it is possible to convey parts to an assembly line without causing damage to the regions of the parts that are required to have dimensional precision.

Abstract: The present invention provides a developing apparatus comprising a developer bearing member for bearing developer, a spacer provided on a surface at an end portion of the developer bearing member along a longitudinal direction, for maintaining a constant gap between the developer bearing member and an image bearing member for supplying the developer from the developer bearing member, a seal member for regulating leakage of the developer toward the end portion of the developer bearing member along the longitudinal direction, and a developer scraping member provided at a portion overlapping with the seal member along the longitudinal direction of the developer bearing member, contacting the developer bearing member, and wherein the developer bearing member contacts a surface of the spacer.