Abstract: A disclosed developing device includes a developer carrier including a developing sleeve and a magnetic roller provided inside the developing sleeve. The magnet roller includes a regulating magnetic pole and a pump-up magnetic pole that have different polarities from each other. Among an entire region of the moving surface of the developing sleeve in the surface movement direction, a maximum pump-up magnetic force position where the pump-up magnetic force of the pump-up magnetic pole is maximum faces an upstream position with respect to a supplying position at which the developer is supplied from a supplying screw to the developing sleeve.

Abstract: A disclosed developing device is for accommodating a developer including carriers and a toner, and for developing a latent image formed on an image carrier. The developing device includes plural developer conveying units configured to convey the developer accommodated in the developing device and form circulating paths; and a ventilation unit configured to perform ventilation between at least one of the developer conveying units whose internal pressure increases and at least one of the developer conveying units whose internal pressure decreases.

Abstract: In a developing device, a receive-convey screw conveys a developer received from a developer carrier. The receive-convey screw includes a receive-convey blade including a lower, outer circumferential end located in a downstream end of the receive-convey blade in the developer conveyance direction of the receive-convey screw. A slant-convey screw is disposed obliquely relative to an axial direction of the receive-convey screw, and conveys the developer received from the receive-convey screw upward. The slant-convey screw includes a slant-convey blade including a lower, outer circumferential end located in an upstream end of the slant-convey blade in the developer conveyance direction of the slant-convey screw, the lower, outer circumferential end being located at a height level lower than the lower, outer circumferential end of the receive-convey blade.

Abstract: A bearing detachably and rotatably holds a photoconductor. A bearing holder firmly holds the bearing. A rotating lever is provided on a rotation axis of a photoconductor between the photoconductor and the bearing holder. The bearing holder and the rotating lever are provided with many protrusions at regular intervals. At a first relative position of the bearing holder and the rotating lever, the protrusions on the bearing holder are located in between the protrusions on the rotating lever. At a second relative position of the bearing holder and the rotating lever, the protrusions on the bearing holder ride on the protrusions on the rotating lever thereby pushing the photoconductor away from the bearing and detaching the photoconductor from the bearing.

Abstract: A developing device includes first-third sections, a developing roller, a partitioning wall and a toner concentration detector. The first-third sections have first-third screw augers respectively. The partitioning wall isolates the third section from the first section and the second section. A supply opening is formed in a portion of the partitioning wall opposing the first section. A toner concentration detector is disposed in the third section. The first screw auger conveys developer including toner to the developing roller, into the third section via the supply opening, and into the second section. The second screw auger conveys developer accommodated in the second section into the third section. The third screw auger conveys developer accommodated in the third section into the first section. Toner is replenished into the third section based on a detection result by the toner concentration detector.

Abstract: A developing device that can suitably discharge developer from the developing device by the amount of developer in the developing device increased by carrier supplemented into the developing device, including: a supply transport screw and a receiving transport screw, the rotational axes of which are mutually parallel in relation to an image support member and which are arranged in a top and bottom positional relationship, and an inclined transport screw which is arranged at an incline between one end of the supply transport screw and the other end of the receiving transport screw; supply means for supplying new carrier into a casing; and a discharge port and discharge means for discharging part of the developer housed in the casing to the outside, the discharge port being provided on the part of the casing corresponding to the upper part of the inclined transport screw.

Abstract: A premixed developing system developing device, process cartridge, and image forming apparatus, in which a developing agent thrown up by a transport member is not discharged from a discharge aperture, variation in the quantity of the developing agent discharged to the outside does not occur, and the image quality of images output is stable. A discharge aperture is formed in the wall of a transport path of a transport member to discharge the developing agent to the outside when the surface of the developing agent exceeds a predetermined level. The transport member is provided with an area, in a part in the longitudinal direction, in which a screw portion is not formed. The discharge aperture is disposed opposite to the area, where the screw portion is not formed on the transport member, and is formed such that the length of the discharge aperture is smaller than the length of the area in the longitudinal direction.

Abstract: A developing device, process cartridge and image forming apparatus of a premix developing system, with which developer splashed by the transport member is not discharged from the device, fluctuations of the amount of developer discharged to the outside are not produced, and the output image quality is stable. This developing device is provided with a pocket part, which is installed in a depressed manner facing the outside in relation to the transport route formed by the transport member, and into and out of which part of the developer transported in the transport route flows. This pocket part is provided with a discharge port for discharging developer to outside the device when the surface of the developer flowing into the pocket part exceeds a specified height.

Abstract: A developing device, process cartridge and image forming apparatus of a premix developing system, with which developer splashed by the transport member is not discharged from the discharge port, fluctuations of the amount of developer discharged to the outside are not produced, and the output image quality is stable. The transport member comprises, in a part thereof in the longitudinal direction, a cutaway region where the screw part is not formed. The discharge port faces the cutaway region, and is formed such that the longitudinal length thereof is smaller than that of the cutaway region. A wall part, which protrudes toward the interior of the transport route from a partition wall where the discharge port is formed, is then installed upstream of the transport route in relation to the discharge port and within the range of the cutaway region.

Abstract: To provide a relatively small developing device, process cartridge and image forming apparatus that prevent developer, accommodated in a second developer conveying portion for recovering the developer after a developing step, from being pumped up to a developer carrier, and that do not apply a large stress to the developer. A plurality of developer carriers are arranged side-by-side in a direction of gravitational force so as to face an image carrier.

Abstract: A disclosed developing device includes a developer carrier including a developing sleeve and a magnetic roller provided inside the developing sleeve. The magnet roller includes a regulating magnetic pole and a pump-up magnetic pole that have different polarities from each other. Among an entire region of the moving surface of the developing sleeve in the surface movement direction, a maximum pump-up magnetic force position where the pump-up magnetic force of the pump-up magnetic pole is maximum faces an upstream position with respect to a supplying position at which the developer is supplied from a supplying screw to the developing sleeve.

Abstract: A developing device capable of preventing deterioration of the image quality, which is caused when a developer recovered by a developing roller re-adheres thereto, and an image forming apparatus equipped with the developing device. The developer conveyance amount on the upstream side of an agitation conveyance path in a developer conveyance direction becomes larger than the amount of developer to be transported from a recovery conveyance path to the agitation conveyance path, by making the developer conveyance amount on the upstream side of an agitating screw in the developer conveyance direction equal to or larger than the developer conveyance amount on the downstream side of a recovery screw in the developer conveyance direction. Accordingly, the amount of developer existing on the upstream side of the agitation conveyance path in the developer conveyance direction becomes small, whereby the developer can be delivered smoothly from the recovery conveyance path to the agitation conveyance path.

Abstract: A developing device is disclosed. The developing device includes a developing roller disposed to face an image carrier and a toner carrier capturing roller disposed to face the developing roller for capturing toner carriers adhered onto the image carrier. The developing roller generates a magnetic pole at a side facing the toner carrier capturing roller. A first virtual line, which connects a rotational center of the developing roller to a rotational center of the toner carrier capturing roller, passes through a region between a position where a magnetic flux density of the magnetic pole in the normal line direction is minimum on the developing roller at the upstream side in the rotational direction of the developing roller and a position where the magnetic flux density of the magnetic pole in the normal line direction is maximum on the developing roller.

Abstract: A developing unit containing developer including carrier and toner and developing a latent image formed on an image carrier is disclosed. The developing unit includes multiple conveyor members configured to convey the contained developer in respective longitudinal directions so as to form a circulation channel; a supply part configured to supplement the carrier in the developing unit; a discharge part configured to discharge a first part of the contained developer outside the developing unit; and a bypass channel configured to cause a second part of the developer to return to the upstream side of the circulation channel without passing a position where the discharge part is provided.

Abstract: A disclosed developing device is for accommodating a developer including carriers and a toner, and for developing a latent image formed on an image carrier. The developing device includes plural developer conveying units configured to convey the developer accommodated in the developing device and form circulating paths; and a ventilation unit configured to perform ventilation between at least one of the developer conveying units whose internal pressure increases and at least one of the developer conveying units whose internal pressure decreases.

Abstract: A bearing detachably and rotatably holds a photoconductor. A bearing holder firmly holds the bearing. A rotating lever is provided on a rotation axis of a photoconductor between the photoconductor and the bearing holder. The bearing holder and the rotating lever are provided with many protrusions at regular intervals. At a first relative position of the bearing holder and the rotating lever, the protrusions on the bearing holder are located in between the protrusions on the rotating lever. At a second relative position of the bearing holder and the rotating lever, the protrusions on the bearing holder ride on the protrusions on the rotating lever thereby pushing the photoconductor away from the bearing and detaching the photoconductor from the bearing.

Abstract: A fixing device wherein supposing that the total load given to a heating roller and a pressure roller is W (kgf) and the area of the pressure contact portion of the heating roller with respect to the pressure roller (nip area) is S (cm2), the nip pressure (=W/S) is 2.7 kgf/cm2 or more and the length of the pressure contact portion in the direction parallel to the direction of conveyance of a recording material is defined to be 14 mm or more.

Abstract: A development apparatus includes a first developer chamber configured to store and supply the developer, a first developer bearer configured to convey the developer supplied from the first developer chamber to a first development domain, defined by a portion of the first developer bearer facing a latent image bearer, to develop the latent image, a second developer bearer configured to convey the developer passed through the first development domain to a second development domain, defined by a portion of the second developer bearer facing the latent image bearer, to develop the latent image, a second developer chamber configured to recover the developer passing through the second development domain and store the recovered developer, and a transfer prevention member provided between the second developer chamber and the second developer bearer to reduce a transfer of the developer from the second developer chamber to the second developer bearer.

Abstract: An image forming apparatus includes a latent image carrier and a developing device configured to develop a latent image carried by the latent image carrier. In the developing device, a receive-convey screw conveys a developer received from a developer carrier. The receive-convey screw includes a receive-convey blade including a lower, outer circumferential end located in a downstream end of the receive-convey blade in the developer conveyance direction of the receive-convey screw. A slant-convey screw is disposed obliquely relative to an axial direction of the receive-convey screw, and conveys the developer received from the receive-convey screw upward. The slant-convey screw includes a slant-convey blade including a lower, outer circumferential end located in an upstream end of the slant-convey blade in the developer conveyance direction of the slant-convey screw, the lower, outer circumferential end being located at a height level lower than the lower, outer circumferential end of the receive-convey blade.

Abstract: A cleaning device is disposed substantially vertical above a photosensitive drum for the purpose of constructing a compact electrophotographic printer. The cleaning device includes a housing that accommodates an auxiliary toner conveying part and a sheet-like resilient member. A cleaning brush is also disposed in the housing so that a gap of 1-3 mm is formed between the cleaning brush and the auxiliary toner conveying part and resilient member. During an image forming operation, toner accumulates between the cleaning blade and the cleaning brush and is conveyed upward through the gap between the cleaning brush and the auxiliary toner conveying part and resilient member. The toner drops onto the cleaning brush near the top thereof and is conveyed by the cleaning brush to a screw. The screw discharges the toner from the cleaning device.