Abstract: A developer container includes a developer accommodating portion, a rotatable member, and a flexible sheet member. The developer container further includes an elastically deformable elastic member. With respect to a longitudinal direction of the developer accommodating portion, between an end portion of the rotatable member and an inside surface of the developer accommodating portion, a gap is formed to permit movement of the rotatable member relative to the developer accommodating portion. In an unused state, the sheet member is elastically deformable together with the elastic member by the movement of the rotatable member relative to the developer accommodating portion in the longitudinal direction.

Abstract: In a developing device, a rotation shaft is provided with a developer feeding member, a cleaning member, and a receiving portion. The receiving portion is provided downstream of the developer feeding member and upstream of a light transmitting member, provided to a wall surface of a developer accommodating chamber of the developing device, with respect to a rotational direction of the rotation shaft when the cleaning member has passed through the light transmitting member.

Abstract: A developing device includes: a developer holding body including: a hollow development rotary body which is opposed to an image holding body capable of holding a toner image and has a smooth surface whose surface roughness is lower than or equal to 5 ?m in terms of maximum height; and a magnet member which is fixedly housed in the development rotary body and in which a plurality of magnetic poles are arranged alongside its periphery, the developer holding body operating in such a manner that developer containing toner and carrier is held on the development rotary body by magnetic force produced by the magnetic poles of the magnet member as the development rotary body is rotated; a layer regulating rotary body as defined herein; and a development driving device as defined herein.

Abstract: A developing device configured such that the developing device or the like can be easily inserted and removed without increasing the size of the apparatus, and an image forming apparatus that uses this developing device as well as a process cartridge. The developing device is provided with a first rib formed projecting from a first main wall surface, which is the side surface with the maximum area in the chassis of the developing device, and a second rib formed projecting from a second main wall surface, which is the side surface in opposition to the first main wall surface, the first rib being disposed in a position higher than the second rib in the height direction.

Abstract: A color image forming apparatus includes a photoreceptor medium, an exposing unit, a plurality of developer units, and a power supply. The exposing unit scans light onto the photoreceptor drum to form a latent electrostatic image. The plurality of developer units include developer rollers supplying toner to the latent electrostatic image to develop the latent electrostatic image into a toner image. Each developer unit contains toner of a different color, and the developer units are arranged around the photoreceptor medium so that the developer rollers are separated by a development gap from the photoreceptor medium. The power supply selectively applies a first bias allowing toner to be supplied through the development gap to the photoreceptor medium on which the latent electrostatic image is formed and a second bias preventing toner from passing through the development gap.