Abstract: A developer cartridge is used with an image forming apparatus. The developer cartridge has a groove which formed in a longitudinal end surface of thereof and extends in an insertion direction of the cylinder. A strip-shaped projection formed in the image forming apparatus projects extends in the insertion direction. When the developer cartridge is fully inserted into the image forming apparatus, the groove receives the projection so that the projection is at a predetermined position relative to the developer cartridge. Two first walls define the groove which is progressively wide as the circumference is approached. A second wall rises from the longitudinal end surface of the developer cartridge and is continuous with one of the two first opposed walls. The second wall smoothly guides the projection into the groove.

Abstract: A color image forming apparatus includes a carrier belt which runs along a transport path of a recording medium to transport the recording medium. A number of image-forming sections are aligned in the transport path. Each of the plurality of image-forming sections forms a toner image of a corresponding color included in an image signal. A plurality of transfer units are provided, with each being disposed to oppose a corresponding one of the number of image-forming sections. Each of the number of transfer units transferring the toner image of the corresponding color to the recording medium. A fixing unit is provided that fixes the toner image to the recording medium. A controller is provided that detects a number of colors in the image signal. The controller sets one set of speeds from a plurality of different sets of speeds in accordance with the number of colors.

Abstract: A developer cartridge is used with an image forming apparatus. The developer cartridge has a groove which formed in a longitudinal end surface of thereof and extends in an insertion direction of the cylinder. A strip-shaped projection formed in the image forming apparatus projects extends in the insertion direction. When the developer cartridge is fully inserted into the image forming apparatus, the groove receives the projection so that the projection is at a predetermined position relative to the developer cartridge. Two first walls define the groove which is progressively wide as the circumference is approached. A second wall rises from the longitudinal end surface of the developer cartridge and is continuous with one of the two first opposed walls. The second wall smoothly guides the projection into the groove.

Abstract: A color image forming apparatus provides the prolonged life of the photosensitive drums, carrier belt, and toner of the respective colors and improves the quality of the printed color image. A carrier belt transports a recording medium placed thereon so that the recording medium passes through a plurality of printing mechanisms which print images of different colors on the recording medium in superposition. Each printing mechanism prints an image of a corresponding color. The printing mechanism is adapted to be moved into its operative position where the photosensitive drum of the printing mechanism is in contact with the carrier belt to print the image on the recording medium, and into its non-operative position where the photosensitive drum of the printing mechanism is not in contact with the carrier belt.

Abstract: A toner image fixing device in an electrophotographic image forming apparatus has a heating roller containing a heater and a backup roller, a surface of which is in contact with a surface of the heating roller. A toner image on the paper is fixed by causing the paper to pass through a contacting portion of the heating roller and the backup roller. The toner image fixing device also has a driving device for supplying driving power to the heating roller or the backup roller to rotate both the heating roller and the backup roller, and a controller. The controller controls the driving section in such a way that both the heating roller and the backup roller begin to rotate intermittently immediately after an electric power supply switch of the apparatus is turned on and heat generation from the heater is initiated, and subsequently begin to rotate continuously when the backup roller achieves one revolution by the intermittent rotation.

Abstract: An electrophotographic printer which includes a developing device for developing an electrostatic latent image formed on the surface of a photoconductor by adhering a developer thereto, a cleaning device for collecting the developer which remains on the photoconductor for reuse after the transference of the developer, and a toner recycling route for flowing the collected developer from the cleaning device back to the developing device by gravity. The photoconductor is exposed to a light source prior to the developer being applied to the surface of the photoconductor.

Abstract: A detachable toner cartridge for use in an electrophotographic printer includes an outer cylinder and an inner cylinder contacting each other and having respective toner discharge outlets that can be overlapped with each other by turning the inner cylinder relative to the outer cylinder so as to discharge toner. The inner cylinder is pressed against the outer cylinder in the circumferential direction to bring the cylinders into close contact to prevent toner leakage. The toner cartridge does not require so high accuracy in manufacturing thereof.

Abstract: A developing device suitable for use in an electrophotographic recording apparatus includes either a toner stirring portion arranged in a toner hopper portion, the toner stirring portion being provided with a portion for varying toner conveying speed, or in the toner a toner stirring and moving means provided in a toner cartridge. A printing irregularity does not occur on a printing paper even if the printing is performed at the state where the amount of toner, which is collected in the toner hopper portion, is too reduced to sufficiently cover the toner hopper stirring portion.

Abstract: An image forming device for printing images on sheets of material includes a photosensitive member for carrying a latent image thereon, a developing roller rotatably disposed adjacent to the photosensitive member for supplying a layer of toner to the photosensitive member through rotation, and a developing blade adjustably disposed adjacent to the developing roller for regulating the thickness of the toner layer supplied to the photosensitive member. A driving circuit controllably rotates the developing roller, and a controller controls the driving circuit. The controller generates signals to control the driving circuit to reverse the rotation of the developing roller under certain conditions.