Abstract: A developer carrying member of a developer apparatus includes a developer carrying surface having a plurality of grooves, wherein a depth D (mm) of the grooves, a width W (mm) of the grooves, and a volume average particle diameter of the magnetic carrier D50 (mm) satisfy, D (mm)>D50 (mm)×½, and W (mm)>D50 (mm), a magnet, provided inside the developer carrying member, attracts the developer on the developing carrying surface, and a regulating member, provided spaced from the developer carrying member, regulates an amount of the developer carried on the developer carrying surface. An amount M/S (mg/mm2) of the developer carried on a unit area of the developer carrying surface after passing by the regulating member, a gap SB (mm) between a free end of the regulating member and the developer carrying member, a density G (mg/mm3) of the developer, and a groove ratio ? which is a ratio of the grooves in the developer carrying surface satisfy, 0.1?M/S (mg/mm2)?0.45, 0.

Abstract: A developing device includes a developer container, a developing roller, and a doctor member. The developer container contains a developer including a toner and a developer. The developing roller includes a developing sleeve bearing the developer, a magnet roller in the developing sleeve. The doctor member includes a regulating portion regulating an amount of the developer home on the developing sleeve to be a predetermined amount. The regulating portion is disposed with a first distance from the developing sleeve. The developing sleeve is disposed with a second distance from an image hearer, and when the developing sleeve bearing the predetermined amount of developer passes a vicinity of the image bearer, a value obtained by dividing the predetermined amount by the second distance is less than a threshold of occurrence of adherence of the developer to the developing sleeve.

Abstract: An image forming apparatus includes an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a developer including a carrier and a toner. The control portion can perform a development ghost prediction mode that includes a step of measuring the amount of charge of the toner within the developing device at the time of non-image formation, a step of measuring, as a carrier current, the direct-current component of a development current when the amount of development of the toner is 0 [mg/cm2] and a step of estimating the level of occurrence of development ghost and the cause of occurrence based on the amount of charge of the toner and the carrier current which are measured.

Abstract: A developing device includes a housing having an opening in a wall thereof, a developing roller rotatably arranged within the housing, and a magnetic pole structure, wherein the developing roller is configured to carry a developer on an outer surface thereof using the magnetic force of the magnetic pole structure. The developing device further includes a gap forming member located within, and spaced from, the housing at a location downstream, in the rotation direction of the developing roller, of the opening in the wall of the housing, forming a first gap with respect to the developing roller and forming a second gap with respect to the housing, a blocking member arranged in the first gap, and a guide section configured to guide airflow passing through the second gap in a general direction toward the developing roller.

Abstract: A developing apparatus includes a sleeve for carrying a developer including toner and magnetic carrier, the sleeve having a plurality of grooves extending in a longitudinal direction; a magnet provided inside the sleeve, a non-magnetic regulating member, provided spaced from the sleeve, wherein an amount M/S (mg/mm2) of the developer carried on a unit area of the sleeve after passing by the regulating member, a gap SB (mm) between a free end of the regulating member and the sleeve, a density G (mg/mm3) of the developer, and a groove ratio ? which is a ratio of the grooves in the surface of the sleeve satisfy, 0.1?M/S (mg/mm2)?0.5, 0.2?SB (mm), and m/S (mg/mm2)×1/4??×{SB (mm)+D (mm)}×G (mg/mm3)<M/S (mg/mm2).

Abstract: An image forming apparatus, detachably connected to a consumable product including a plurality of function units integrated with each other, includes an acquisition unit that acquires a life of each of the plurality of function units and a setting unit that sets an operation in a case where each acquired life reaches a preset value.

Abstract: A developing device includes a rotatable developing sleeve to carry and feed a developer including toner and a carrier toward a developing region, and a magnetic field generating portion provided inside the developing sleeve and having a developing magnetic pole for forming the developing region. The developing magnetic pole is disposed opposite to a closest position of the image bearing member to the developing sleeve. A ratio of an 80%-value-width of magnetic flux density of the developing magnetic pole with respect to a normal direction of the developing sleeve to a half peak width of the magnetic flux density of the developing magnetic pole with respect to the normal direction is 0.65 or more.

Abstract: A force for warping a regulating blade is imparted to the regulating blade in such a manner that a gap between a developer bearing member supported by a development frame member and the regulating blade attached to an attaching portion of the development frame member falls within a predetermined range over a longitudinal direction of the developer bearing member. The regulating blade is fixed to the attaching portion in a state in which the regulating blade is warped by the force imparted to the regulating blade and the gap is within the predetermined range over the longitudinal direction of the developer bearing member.

Abstract: A carrier for electrostatic image development includes: resin-coated magnetic particles each including a magnetic particle and a resin layer that covers the magnetic particle; and strontium titanate particles composed of primary particles having an average circularity of 0.82 to 0.94 and an 84% cumulative circularity of more than 0.92.

Abstract: An image forming apparatus includes: a first image forming unit that includes a first image holding member and a first developing unit, the first developing unit accommodating a first developer that includes a first toner and a first carrier; a first transfer unit; a second image forming unit that is disposed downstream of the first image forming unit in a traveling direction of a transfer medium and includes a second image holding member and a second developing unit, the second developing unit accommodating a second developer that includes a second toner and a second carrier; and a second transfer unit, in which a volume resistivity of the first carrier is higher than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is more than a volume average particle diameter of the second carrier.

Abstract: A development device includes a magnetic field generation unit having a developing magnetic pole S2, a magnetic pole N2, and a magnetic pole N1. The magnetic poles N2 and N1 are disposed adjacent to the magnetic pole S2, at positions downstream and upstream of the magnetic pole S2 in a rotation direction of a sleeve, respectively. The magnetic pole N2 is configured to have a larger magnetic flux density and full width half maximum in a normal direction of the sleeve and have a smaller inter-pole distance from the developing magnetic pole than the magnetic pole N1, so that the rising position of magnetic brushes of developer is shifted in the upstream direction, and the magnetic brushes come into contact with a photosensitive drum more suitably.

Abstract: A developing device includes a developing roller, a conveyor roller and a developer stirring unit. The developing roller is arranged to face a photoconductive drum at a predetermined developing position. The developing roller includes a fixed first magnet and a first sleeve. The conveyor roller is arranged to face the developing roller at a predetermined facing position. The conveyor roller includes a fixed second magnet and a second sleeve. The developer stirring unit stirs the developer and supplies the developer to the conveyor roller. The first magnet includes a first magnetic pole composed of a predetermined magnetic pole and a second magnetic pole arranged downstream of and adjacent to the first magnetic pole and having the same polarity as the first magnetic pole. The developer is transferred from the developing roller to the conveyor roller after passing through a repulsive magnetic field formed by the first and second magnetic poles.

Abstract: A developing device includes a developer bearer including a magnetic field generator, a developer regulator disposed opposite the developer bearer across a regulation gap, a developer containing compartment disposed below the developer bearer, and a conveying screw disposed in the developer containing compartment and including a shaft having a diameter greater than a radius of the conveying screw. On a cross section perpendicular to an axial direction of the conveying screw, a developer scooping pole of the magnetic field generator to scoop the developer from the developer containing compartment onto the developer bearer is disposed between the regulation gap and a bisector dividing an angle extending from a first line, which connects a center of the developer bearer and a center of the conveying screw, to a second line, which connects the center of the developer bearer and the regulation gap, in a rotation direction of the developer bearer.

Abstract: A developing device includes a developing roller, a toner supply roller, a regulating blade, a casing, and a cleaning member. The developing roller supplies a toner to the image carrier in a region opposed to an image carrier. The toner supply roller is located opposed to the developing roller. The toner supply roller forms a magnetic brush made of a two-component developer including a magnetic carrier and a toner on an outer peripheral surface to supply a toner to the developing roller in a region opposed to the developing roller. The regulating blade is located opposed to the toner supply roller at a predetermined interval. The casing houses the developing roller, the toner supply roller, and the regulating blade. The cleaning member reciprocates along a longitudinal direction of the regulating blade so as to remove a toner accumulated on a top surface of the regulating blade.

Abstract: A developing sleeve includes first axially extending groove portions which satisfy D1?2R and W1?2R, where 2R is a volume-average particle size of a carrier, D1 is a maximum depth of each first groove portion and W1 is a width an opening of each first groove portion with respect to a circumferential direction of the developing sleeve, and second axially extending groove portions. Each second groove portion satisfies D2<2R, where 2R is the volume-average particle size of the carrier and D2 is a maximum depth of each second groove portion. Each or a plurality of the second groove portions are disposed between the first groove portions with respect to the circumferential direction of the developing sleeve.

Abstract: A developing device includes a storage portion, a developer carrying member, a stirring portion, a layer thickness restricting portion, and a guide portion. The guide portion is disposed between the stirring portion and the layer thickness restricting portion. The stirring portion faces the developer carrying member with a first gap between them. The layer thickness restricting portion faces the developer carrying member with a second gap between them. The guide portion includes a first guide surface and a second guide surface. On the first guide surface, convex portions or concave portions are formed. The first guide surface faces the stirring portion with, between them, a third gap that is a passage through which the developer passes toward the first gap. The second guide surface faces the developer carrying member with, between them, a fourth gap that is a passage through which the developer passes toward the second gap.

Abstract: A developing device includes a developing roller, a conveyor roller, a developer stirring unit and a development bias applying unit. The developing roller is arranged to face a photoconductive drum at a predetermined developing position and supplies the toner. The conveyor roller is arranged to face the developing roller at a predetermined facing position and supplies the developer to the developing roller. The development bias applying unit applies development biases to the first sleeve of the developing roller and the second sleeve of the conveyor roller during a developing operation of developing the electrostatic latent image on the photoconductive drum with the toner. The development bias applying unit applies the development biases such that a shifting electric field to move the toner on the first sleeve of the developing roller toward the second sleeve of the conveyor roller is formed at the facing position during the developing operation.

Abstract: A multipolar magnet is arranged inside a developer bearing member. A partitioning wall is arranged such that an apex position thereof is located between the developer bearing member and a first conveying member, and is extended up to a position which is located below an upper end position of a zone. A plurality of concaved portions is formed on the surface of the developer bearing member at an interval. Each of the plurality of concaved portions has such an opening shape that a maximum diameter of an inscribed circle is equal to or greater than a diameter of an average grain size of a carrier, and is formed such that the carrier with the average grain size is able to enter each of the concaved portions by a depth that is equal to or greater than a radius thereof.

Abstract: A developing unit includes a developer carrier, and first and second chambers to collect and circulate developer. A partition separates the first and second chambers and has first communication portion disposed more downstream in the second chamber and a second communication portion disposed more upstream in the second chamber. A first conveying member is disposed in the first chamber, and a second conveying member is disposed in the second chamber and includes a spiral blade portion, a reverse spiral blade portion helically wound in an opposite direction of the spiral blade portion and disposed downstream of the spiral blade portion, and a discharging portion provided downstream of the reverse spiral blade. An upstream end of the first communication portion is positioned farther than a downstream end of the second communication portion from a center of the developer carrier in a rotational axis direction of the developer carrier.

Abstract: An image forming apparatus includes at least one image bearer; multiple developing devices to develop the latent images with developers including toner and carrier into a toner image; multiple developer supply devices to supply the developers to the multiple developing devices, respectively; and a fixing device to fix the toner image on a sheet of recording media. When one of the multiple developing devices positioned at a shortest distance from an outline of the fixing device is referred to as a first developing device, and one of the multiple developer supply devices that supplies developer to the first developing device is referred to as a first developer supply device, the first developer supply device is greater in percentage by weight of carrier in developer supplied to the first developing device than rest of the multiple developer supply devices.

Abstract: A developer unit for a dual component development electrophotographic image forming device according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. An auger is positioned to convey developer mix in the reservoir toward the outer surface of a magnetic roll on a front of the housing. A ledge on an inner surface of the housing extends axially with respect to the magnetic roll along a front of the reservoir. The ledge is positioned upstream from a trim bar and downstream from a pickup pole of the magnetic roll with respect to the operative rotational direction of the magnetic roll. The ledge has a concave curved inner surface that is open to the reservoir and extends from near the trim bar to near a front side of the auger.

Abstract: A development device wherein a magnetic force distribution of a developer bearing member in a longitudinal direction at positions at which a magnetic flux density of a low magnetic field area is minimal in the peripheral direction of the developer bearing member is set such that a difference between a maximum magnetic flux density in a range from a maximum position at which an attenuation rate of the magnetic flux density is maximal to a 30 mm distant position toward the center of the developer bearing member and a magnetic flux density on a further center side of the developer bearing member than the range is 3 mT or less, and an absolute value of the magnetic flux density of a further outer side in the longitudinal direction of the developer bearing member than the maximum position is set to 3 mT or less.

Abstract: An image forming apparatus includes: a developer carrying member (sleeve) including a magnet and grooves; and an image bearing member (drum). The electrostatic image on the drum is developed with a developer. When a linear speed of the sleeve is Vs, a linear speed of the drum is Vd, a peripheral speed ratio of the sleeve to the drum is ?=Vs/Vd, a radius of the sleeve is Rs, a radius of the drum is Rd, a distance of a rectilinear line connecting a most upstream point and a most downstream point in the developing region with respect to the circumferential direction is Lnip, a pitch of the grooves of the sleeve is p, and an arbitrary natural number is n, the following relationship is satisfied: (1?0.05)×np?2[?×Rd×arcsin(Lnip/2Rd)?Rs×arcsin(Lnip/2Rs)]?(1+0.05)×np.

Abstract: A developing device includes a first developer holder and a second developer holder. The first developer holder is disposed so as to face an image holding member and rotates so as to move in a direction opposite to a direction of movement of the image holding member at a first facing portion. The second developer holder is disposed downstream from the first developer holder in the direction of movement of the image holding member so as to face the image holding member and rotates so as to move in the same direction as the image holding member moves at a second facing portion. A value obtained by dividing an amount of developer per unit area held on the first developer holder by a shortest distance between the image holding member and the first developer holder is approximately in a range from 1.00×103 kg/m3 to 1.60×103 kg/m3.

Abstract: Disclosed is a method for managing the triboelectric charge potential of a two-component xerographic developer over a wide range of variables. In particular, the present embodiments uses the addition of second and third carrier particles to a developer comprising toner particles and first carrier particles to adjust the tribo electric charge potential of the developer. Various parameters (system responses), including Vmag, laser power, relative humidity, toner and carrier age, and image scan data, are used to determine the requisite amounts of the second and third carrier to achieve a desired shift in tribo electric charge potential of the developer.

Abstract: An electro-photographic print system or method for regulating a supply of toner based on a required toner amount.

Abstract: An image forming apparatus includes a first image forming unit and a second image forming unit, wherein the first image forming unit is arranged on a downstream side of the second image forming unit in a traveling direction of a transfer medium, the first developing unit contains a first developer containing a first toner and a first carrier, the second developing unit contains a second developer containing a second toner and a second carrier, and a ratio of a resistance value of the first carrier to a resistance value of the second carrier is within a range of from 4.0×10?5 to 9.7×10?1.

Abstract: A developing apparatus includes a developer carrying member; and a magnetic member provided inside the carrying member and having magnetic poles arranged circumferentially, wherein on a center axis of the carrying member outside an end of the magnetic member, there is a region in which a magnetic flux density of a first magnetic polarity converges toward zero; and wherein a ratio of a volume, per unit length, of a portion of the magnetic member which has a surface magnetic pole of a second magnetic polarity which is different from the first magnetic polarity in a longitudinal end portion to that in a longitudinally central portion is smaller than a ratio of a volume of a portion of the magnetic member which has a surface magnetic pole of the first magnetic polarity in a longitudinal end portion to that in a longitudinally central portion.

Abstract: A developing device includes: a developer carrying member; a first chamber; a second chamber; a partition wall; a communicating portion; and a feeding member, provided rotatably in the first chamber, for feeding the developer in the first chamber. In a circulation path, the feeding member includes a first region corresponding to a developer coating region of the developer carrying member and a second region, provided downstream of the first region with respect to a feeding direction of the feeding member, corresponding to a region outside the developer coating region of the developer carrying member. Feeding power per unit driving time of the feeding member is set at a smaller value in the first region than in the second region.

Abstract: A magnet roller includes a roller-shaped body constructed of a magnetic field generating material, a first support rod provided to a first axial end of the body; and a second support rod provided to a second axial end of the body. At least one of the first and second support rods is constructed of a nonmagnetic material and includes a projecting part projecting outside the body from an end face of the body and a buried part united to the projecting part and positioned inside the body. The buried part includes a reduced-area portion smaller than a base end of the projecting part adjacent to the buried part in cross-sectional area perpendicular to an axial direction of the first and second support rods.

Abstract: A two-component developer includes toner and a magnetic carrier. The two-component developer is used in a developing device including a circular cylindrical developer transporting member that is disposed so as to be separated by 125 ?m to 250 ?m from a latent image carrier that rotates. The two-component developer is used so as to satisfy a condition in which a width of a region where a magnetic brush contacts a surface of the latent image carrier is in a range of from 1.0 mm to 2.25 mm, and a condition in which a developer density of the region where the magnetic brush contacts the surface of the latent image carrier is in a range of from 0.75×10?6 to 1.50×10?6 g/m3.

Abstract: An image forming apparatus includes a controller that controls rotational driving of a magnetic roller and rotational driving of a developing roller. The controller is capable of performing a toner collecting mode when no image formation is performed. In the toner collecting mode, the magnetic roller and the developing roller are intermittently rotated in a direction reverse to a direction in which the magnetic roller and the developing roller are rotated during image formation, then the magnetic roller is made to rotate in a forward direction, and then, the magnetic roller is rotated in a backward direction.

Abstract: A developing device includes a first developer carrier that carries developer on a peripheral surface thereof; a second developer carrier that carries the developer on a peripheral surface thereof; a supplying section that supplies the developer to the peripheral surface of the first developer carrier; a layer thickness regulating member that regulates a layer thickness of the developer supplied to the peripheral surface of the first developer carrier by the supplying section; a first transfer magnetic pole disposed in an interior of the first developer carrier; a second transfer magnetic pole disposed in an interior of the second developer carrier; a first downstream magnetic pole disposed in the interior of the first developer carrier; and a second downstream magnetic pole disposed in the interior of the second developer carrier.

Abstract: A developing apparatus used in an image forming apparatus including a developer bearing member configured to develop a latent image formed on an image bearing member and rotate together with the image bearing member so that opposed surfaces thereof rotate in the same direction, an interval guarantee member configured to maintain a distance between the developer bearing member and the image bearing member by coming into abutment with the developer bearing member and the image bearing member, and a biasing member configured to bias the interval guarantee member toward the upstream side in the direction of rotation of the developer bearing member by applying an elastic force generated by elastic deformation on the interval guarantee member.

Abstract: A developing device includes a developer bearer, a magnetic field generator provided inside the developer bearer, a casing including an opening to partly expose a surface of the developer bearer, and a lateral end cover to cover an axial end portion of the exposed surface of the developer bearer. The lateral end cover includes a wide portion extending more to an axial inner side of the developer bearer than a downstream portion of the lateral end cover positioned downstream from the wide portion in a direction of rotation of the developer bearer. A downstream end of the wide portion is downstream from an upstream end of the development range in the direction of rotation of the developer bearer.

Abstract: An image forming apparatus includes an image forming section including an image carrier and a developing device, and a developer recovery mechanism. The developing device includes, a developer carrier, and a developer discharge portion. The image forming section incorporates a developing device employing a first developing method where toner is caused to adhere to the image carrier by a magnetic brush formed on the developer carrier, or a developing device having a toner carrier between the developer carrier and the image carrier, and employing a second developing method where a toner layer is formed on the toner carrier by a magnetic brush formed on the developer carrier, and toner is caused to adhere to the image carrier by the toner layer formed on the toner. These developing devices, in the image forming section, each have a same positional relationship between the developer discharge portion and an image-carrier rotation shaft.

Abstract: A developing device includes first and second magnet members respectively including first and second transfer magnetic poles that have different polarities, that generate a magnetic force for transferring a developer from a first developer-transporting member to a second developer-transporting member, and that are located at positions where the developer-transporting members come close to each other, wherein (B1×B2)/L2 is less than about 400 where L represents a distance (mm) between an outer peripheral surface portion of the first developer-transporting member, the portion facing the first transfer magnetic pole, and an outer peripheral surface portion of the second developer-transporting member, the portion facing the second transfer magnetic pole, and B1 and B2 (mT) respectively represent maximum magnetic flux densities of the first and second transfer magnetic poles in a normal line direction on outer peripheral surfaces of the first and second developer-transporting members.

Abstract: In accordance with one embodiment, a developing apparatus comprises a developing roller configured to hold developing agent and face to an image carrier; a housing configured to store the developing agent and support the developing roller; and a first gap adjusting section configured inside the housing at the downstream side of an opening end part of the housing in a rotation direction of the developing roller, and configured to protrude from an inner wall of the housing at the side parts in an axis direction of the developing roller.

Abstract: A developing device includes a case for housing a developer, a magnetic roller, an agitating member, a layer thickness restricting member and a plurality of projection members. The magnetic roller is arranged in the case, includes a rotary shaft and magnetically carries the developer on a circumferential surface. The agitating member is arranged to face the magnetic roller in the case, includes a shaft center and a screw forming portion arranged around the shaft center. The layer thickness restricting member restricts the layer thickness of the developer to a predetermined thickness. The plurality of projection members are arranged along a rotation axis direction of the magnetic roller to face the circumferential surface of the magnetic roller at a side upstream of the layer thickness restricting member in a rotating direction of the magnetic roller and comes into contact with the developer carried on the magnetic roller.

Abstract: An image forming apparatus, wherein the packing density at a closest point where the first peripheral surface and the second peripheral surface are the closest to each other is within a range from 0.3 to 0.4; wherein a maximum magnetic flux density of a principal magnetic pole for generating the magnetic field for development is located in an upstream side from the closest point with respect to the specified direction and at a point where the packing density is equal to or greater than 0.2; and wherein a magnetic flux density of the principal magnetic pole at a point where the packing density is 0.2 in a downstream side from the closest point with respect to the specified direction is equal to or less than ½ of a magnetic flux density of the principal magnetic pole at a point where the packing density is 0.2 in the upstream side.

Abstract: A development device includes a developer container, a developer carrier, exposed partly from a casing, facing a latent image carrier in a development area, a magnetic field generator inside the developer carrier, having multiple magnetic poles including a conveyance pole to convey the developer downstream from the development area to a developer release portion, a developer agitator, and a developer regulator. A predetermined gap is kept between an outer surface of the developer carrier and an inner wall of the casing downstream from an opening of the casing, upstream from a developer release portion, in a direction in which the developer carrier rotates. Multiple recesses are formed in the outer surface of the developer carrier at a pitch in a circumferential direction shorter than half a width of a magnetic flux density of the developer conveyance pole in a direction perpendicular to an axial direction of the developer carrier.

Abstract: The image forming apparatus is an image forming apparatus including an image bearing member, a developing device, a transfer device, and a cleaning device. The developing device includes a toner bearing member having a surface subjected to alumite treatment. Toner that is used in the image forming apparatus is magnetic mono-component developer including magnetic toner particles containing at least binder resin and iron-containing magnetic powder, and an external additive to be externally added to the magnetic toner particles. The external additive is formed from inorganic fine particles which have been subjected to surface treatment with a tin-containing compound and an antimony-containing compound. In the image forming apparatus, the ratio of antimony to iron of the toner that has been removed by the cleaning device is double or more the ratio of antimony to iron of the toner before being conveyed by the toner bearing member.

Abstract: An image forming apparatus includes a developer containing part, a developer mixer, a mixer drive motor, a magnetic sleeve, a sleeve drive motor, a mixer rotation speed determination part and a motor drive controller. The developer containing part contains a two-component developer including a toner and a carrier. The developer mixer is provided in the developer containing part, agitates the two-component developer, and charges the toner and the carrier. The mixer rotation speed determination part determines the mixer rotation speed of the mixer drive motor according to a supply amount of the toner supplied to the developer containing part from a toner cartridge by driving of a toner supply motor. The motor drive controller independently performs rotation control of the sleeve drive motor and the mixer drive motor, and rotates and controls the mixer drive motor at the mixer rotation speed determined by the mixer rotation speed determination part.

Abstract: A developing apparatus includes a developing container for accommodating developer including magnetic particles, a developer carrying member, rotatably provided in the developing container, for carrying the developer to a region where the developer carrying member is opposed to image bearing member, and a magnet stationarily provided in the developer carrying member, having a pair of magnetic poles of the same polarity adjacent to each other in a circumferential direction of the developer carrying member. In addition, a magnet member extends at each of longitudinal end portions of the developer carrying member within a circumferential range opposed to and between a half-peak width zone of one of the magnetic poles and a half-peak width zone of the other one of the magnetic poles. A side of the magnet member opposed to the developer carrying member is magnetized only to a polarity which is the same as the polarity of the pair of magnetic poles.

Abstract: A developing unit includes a casing, a developer carrier, a developer conveying path, a developer conveying member, and a layer thickness regulator. The developer carrier is driven to rotate in the casing and carries a toner on the circumferential surface. The developer conveying member is located in the developer conveying path and driven to rotate so as to convey the developer in a second direction and to supply the toner to the developer carrier. The layer thickness regulator is spaced from the developer carrier, and regulates a layer thickness of the developer supplied to the developer carrier. The developing unit is configured to satisfy a condition of 2.0<Vd/Vs<7.0, where Vd denotes a circumferential velocity of the developer carrier and Vs denotes a circumferential velocity of the developer conveying member.

Abstract: An image forming apparatus supplies toner to an electrostatic latent image on a circumferential surface of a photosensitive rotating member to develop the electrostatic latent image, and includes: a photosensitive unit including the photosensitive rotating member and a pair of support frames rotatably supporting the photosensitive rotating member at axial ends thereof; a developing unit including a developing sleeve that is longer in a rotational axis direction thereof than an element tube of the photosensitive rotating member in a rotational axis direction thereof, and a pair of bearings provided outward from axial ends of the element tube and rotatably holding the developing sleeve at axial ends thereof; and a forcing member relatively forcing the developing unit toward the photosensitive unit to bring the bearings into abutment with the respective support frames, such that a gap between the developing sleeve and the photosensitive rotating member is maintained at a predetermined value.

Abstract: A developing device includes a developing member including a scooping pole generating the magnetic lines of force to scoop up a developer, rotating while holding the developer scooped up by the scooping pole on a surface thereof, and supplying the developer to an image holding body to develop the electrostatic latent image, and an agitation transport unit that is disposed at a position where a developer used for development and separated and falling from the developing member is received, rotates about a rotating shaft extending along a rotating shaft of the developing member, agitates the developer, and transports the agitated developer to a scoop position, wherein the scooping pole is disposed on the downstream side of a line, which connects the rotating shaft of the developing member with the rotating shaft of the agitation transport unit, in a rotation direction of the developing member.

Abstract: In a development device, a developer carrier arranged in a housing containing a one-component developer has a circumferential surface carrying the developer. A developer conveying path includes one conveying path along the developer carrier in a first direction and another conveying path in a second direction opposite to the first direction. The developer is circulated and conveyed between the conveying paths. A developer conveying member is arranged in the one conveying path and rotationally driven to convey the developer along the first direction and to supply the developer to the developer carrier. A layer thickness adjusting member is arranged at a distance from the circumferential surface to adjust a layer thickness of the developer supplied to the developer carrier. The developer carrier has a circumferential speed Vd and the developer conveying member has a circumferential speed Vs so that a circumferential speed ratio Vd/Vs satisfies a relationship represented by 1.3?Vd/Vs?5.0.

Abstract: An image forming apparatus for forming a toner image on a print medium with a developer composed of toner and carriers, wherein when the first distance is longer than the second distance, an average gap between the first peripheral surface and a member that faces to the first peripheral surface in an area with a length of the first distance extending upstream from the closest point with respect to the specified direction is smaller than an average gap between the first peripheral surface and a member that faces to the first peripheral surface in an area with a length of the first distance extending downstream from the closest point with respect to the specified direction.

Abstract: A two-component developer includes toner and a magnetic carrier. The two-component developer is used in a developing device including a circular cylindrical developer transporting member that is disposed so as to be separated by 125 ?m to 250 ?m from a latent image carrier that rotates. The two-component developer is used so as to satisfy a condition in which a width of a region where a magnetic brush contacts a surface of the latent image carrier is in a range of from 1.0 mm to 2.25 mm, and a condition in which a developer density of the region where the magnetic brush contacts the surface of the latent image carrier is in a range of from 0.75×10?6 to 1.50×10?6 g/m3.