Abstract: An image forming apparatus includes an image bearing member; a plurality of developing devices for developing electrostatic images formed on the image bearing member with developers, the developing devices including respective developer carrying members for carrying respective developers; moving means for moving a selected one of the developing devices to an operative position, wherein each of the developer carrying members is movable selectively to be in contact with or spaced from the image bearing member at the operative position; wherein the apparatus is operable in a first image formation mode in which an image is formed using the plurality of developing devices and a second image formation mode in which an image is formed using one of the plurality of developing devices, and wherein the developer carrying member which is at the operative position in the first image formation mode is capable of being spaced from the image bearing member by a first distance during non-developing-operation, and the develop

Abstract: A developing cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, the developing cartridge includes a developing roller, for developing an electrostatic latent image formed on an electrophotographic photosensitive member, having an elastic roller portion and a shaft portion supporting the elastic roller portion, a developer regulating member contactable to the elastic roller portion to regulate an amount of the developer deposited on the elastic roller portion; a protecting member including a contact portion provided at a side for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member; and a supporting portion for supporting the contact portion, the supporting portion being provided at a side for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member, wherein the

Abstract: A color printer has multiple developing-agent-containing cartridges each having storage units, and a cartridge holding unit for rotatably holding the developing-agent-containing cartridges. With one of the multiple developing-agent-containing cartridges positioned at an image formation position, a latent image on an image carrying member is developed by the developing agent contained in the developing-agent-containing cartridge. An access position where the storage units of the developing-agent-containing cartridges are accessed is a position other than the image formation position. This provides an image formation device and a control method thereof whereby storage units provided to developing-agent-containing cartridges can be accessed in a precise manner.

Abstract: A developing cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The cartridge includes a developing roller, for developing an electrostatic latent image formed on an electrophotographic photosensitive member, having an elastic roller portion and a shaft portion supporting the elastic roller portion, a developer regulating member; a protecting member including a contact portion provided for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member; and a supporting portion for supporting the contact portion and provided for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member. The contact portion has a hardness which is not less than a predetermined value and not more than a hardness of the elastic roller portion.

Abstract: A color printer has multiple developing-agent-containing cartridges each having storage units, and a cartridge holding unit for rotatably holding the developing-agent-containing cartridges. With one of the multiple developing-agent-containing cartridges positioned at an image formation position, a latent image on an image carrying member is developed by the developing agent contained in the developing-agent-containing cartridge. An access position where the storage units of the developing-agent-containing cartridges are accessed is a position other than the image formation position. This provides an image formation device and a control method thereof whereby storage units provided to developing-agent-containing cartridges can be accessed in a precise manner.

Abstract: A color printer has multiple developing-agent-containing cartridges each having storage units, and a cartridge holding unit for rotatably holding the developing-agent-containing cartridges. With one of the multiple developing-agent-containing cartridges positioned at an image formation position, a latent image on an image carrying member is developed by the developing agent contained in the developing-agent-containing cartridge. An access position where the storage units of the developing-agent-containing cartridges are accessed is a position other than the image formation position. This provides an image formation device and a control method thereof whereby storage units provided to developing-agent-containing cartridges can be accessed in a precise manner.

Abstract: There is provided an image forming apparatus such as a latent image forming apparatus, in which the density of a half tone is stable independent on a write position of a main scanning line, even if a plurality of semiconductor lasers are used. The image forming apparatus has a latent image forming unit for pulse-width-modulating a drive signal of the semiconductor laser in response to the write position of image data. The latent image forming unit has an image sorting circuit for sorting the image data into an odd line and an even line, a memory for storing a turning on position, a pulse generating position control circuit for generating a pulse generating position signal, a PWM circuit for generating a triangular wave in accordance with the pulse generating position signal, and a beam-A-circuit and a beam-B-circuit, which control beams from the semiconductor laser.

Abstract: An image forming apparatus includes an image bearing member; a plurality or developing devices for developing electrostatic images formed on the image bearing member with developers, the developing devices including respective developer carrying members for carrying respective developers; moving means for moving a selected one of the developing devices to an operative position, wherein each of the developer carrying members is movable selectively to be in contact with or spaced from the image bearing member at the operative position; wherein the apparatus is operable in a first image formation mode in which an image is formed using the plurality of developing devices and a second image formation mode in which an image is formed using one of the plurality of developing devices, and wherein the developer carrying member which is at the operative position in the first image formation mode is capable of being spaced from the image bearing member by a first distance during non-developing operation, and the develop

Abstract: A developing cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, the developing cartridge includes a developing roller, for developing an electrostatic latent image formed on an electrophotographic photosensitive member, having an elastic roller portion and a shaft portion supporting the elastic roller portion, a developer regulating member contactable to the elastic roller portion to regulate an amount of the developer deposited on the elastic roller portion; a protecting member including a contact portion provided at a side for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member; and a supporting portion for supporting the contact portion, the supporting portion being provided at a side for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member, wherein the

Abstract: A developing apparatus includes a developer carrying member for carrying a developer to develop an electrostatic image formed on an image bearing member with the developer; a developer regulating member regulates an amount of the developer carried on the developer carrying member; and a controller for controlling a potential difference between the developer carrying member and the developer regulating member such that the potential difference is larger in at least a part of non-developing operation than in a developing operation when the developer carrying member carries the developer.

Abstract: An image forming and apparatus is provided in which a halftone density of an image is stabilized irrespective of a timing at which writing on scanning lines is started, even when using multiple laser beams. First, it is determined whether or not a portion exposed by adjacent laser beams (i.e., exposed by both of two beams simultaneously) is present. If the result of the determination is affirmative, it is then determined whether or not a portion adjacent to the exposed portion and not exposed by a laser beam is present. If the result of this determination is affirmative, exposure by fine dots is added to the portion not exposed by a laser beam.

Abstract: A color printer has multiple developing-agent-containing cartridges each having storage units, and a cartridge holding unit for rotatably holding the developing-agent-containing cartridges. With one of the multiple developing-agent-containing cartridges positioned at an image formation position, a latent image on an image carrying member is developed by the developing agent contained in the developing-agent-containing cartridge. An access position where the storage units of the developing-agent-containing cartridges are accessed is a position other than the image formation position. This provides an image formation device and a control method thereof whereby storage units provided to developing-agent-containing cartridges can be accessed in a precise manner.

Abstract: A developing apparatus includes a developer carrying member for carrying a developer to develop an electrostatic image formed on an image bearing member with the developer; a developer regulating member for regulating an amount of the developer carried on the developer carrying member; and control means for controlling a potential difference between the developer carrying member and the developer regulating member such that the potential difference is larger in at least a part of non-developing operation than in a developing operation when the developer carrying member carries the developer control means for controlling a potential difference between the developer carrying member and the developer regulating member such that the potential difference is larger in at least a part of non-developing operation than in a developing operation when the developer carrying member carries the developer.

Abstract: An image forming and apparatus is provided in which a halftone density of an image is stabilized irrespective of a timing at which writing on scanning lines is started, even when using multiple laser beams. First, it is determined whether or not a portion exposed by adjacent laser beams (i.e., exposed by both of two beams simultaneously) is present. If the result of the determination is affirmative, it is then determined whether or not a portion adjacent to the exposed portion and not exposed by a laser beam is present. If the result of this determination is affirmative, exposure by fine dots is added to the portion not exposed by a laser beam.

Abstract: In an image processing apparatus that includes an order placement means for executing an operation associated with order placement of an expendable used in an image forming apparatus, data associated with image formation is accumulated to have a timing associated with order placement as a trigger, and the operation of the order placement means is controlled on the basis of the accumulated value. In this manner, redundant orders for expendables can be prevented.

Abstract: There is provided an image forming apparatus such as a latent image forming apparatus, in which the density of a half tone is stable independent on a write position of a main scanning line, even if a plurality of semiconductor lasers are used. The image forming apparatus has a latent image forming unit for pulse-width-modulating a drive signal of the semiconductor laser in response to the write position of image data. The latent image forming unit has an image sorting circuit for sorting the image data into an odd line and an even line, a memory for storing a turning on position, a pulse generating position control circuit for generating a pulse generating position signal, a PWM circuit for generating a triangular wave in accordance with the pulse generating position signal, and a beam-A-circuit and a beam-B-circuit, which control beams from the semiconductor laser.

Abstract: An agitating member for agitating a developer includes a metal shaft, a plate member joined to the metal shaft, and a sheet member joined to the plate member, the sheet member being free to curve. A developing apparatus includes a developer bearing member bearing a developer thereon, a developer container containing the developer therein, and the above-described agitating member provided in the developer container for agitating the developer and supplying it to the developer bearing member. A process cartridge detachably attachable to the main body of an image forming apparatus, includes an electrophotographic photosensitive member and the above-described developing apparatus.

Abstract: A charging member is disposed in contact with an electrophotographic photosensitive member and charges the surface of the electrophotographic photosensitive member electrostatically upon application of a voltage. The charging member has a conductive support, a base layer and a surface layer which are formed on the conductive support. The surface layer contains fluorine resin particles as a filler and a fluorine resin as a binder resin.

Abstract: This specification discloses an agitating member for agitating a developer comprising a metal shaft, a plate member joined to the metal shaft, and a sheet member joined to the plate member, the sheet member being free to curve. The specification also discloses a developing apparatus comprising a developer bearing member bearing a developer thereon, a developer container containing the developer therein, and the above-described agitating member provided in the developer container for agitating the developer and supplying it to the developer bearing member. The specification further discloses a process cartridge detachably attachable to the main body of an image forming apparatus, comprising an electrophotographic photosensitive member and the above-described developing apparatus.

Abstract: An image forming apparatus having at least: an image carrying member for carrying an electrostatic latent image, the image carrying member having a photosensitive layer on a conductive substrate; a developer for developing the electrostatic latent image carrying member on the image carrying member; a developer carrying member for carrying the developer and conveying it to a development area; a control member making contact with the developer carrying member for controlling the coating amount of the developer; and a cleaning member for cleaning the surface of the photosensitive layer of the image carrying member by making contact with the surface of the image carrying member with a contact pressure of 0.15N (15 gf) to 0.89N (90 gf). The photosensitive layer contains at least one kind of polycarbonate resin (I) having a viscosity average molecular weight of 1.5×104 or less and at least one kind of polycarbonate resin (II) having a viscosity average molecular weight of more than 1.