Abstract: A developing device, which can inhibit the increase of the rate of uncharged toner caused by long hours of operation and develop an excellent image, and a process cartridge and an image forming apparatus that use such a developing device. A developing sleeve is rotary driven, and has, as magnetic field generating means that is fixedly disposed within the developing sleeve, a magnet roll composed of a plurality of stationary magnets. The magnet roll has five magnetic poles, P1 (south pole), P2 (north pole), P3 (north pole), P4 (south pole) and P5 (north pole), which are arranged in the direction of rotation of the developing sleeve in this order starting from a developing position that is a region facing a photoreceptor.

Abstract: An image forming apparatus includes an image bearing member for bearing an electrostatic latent image; a rotatable developer carrying member, provided opposed to the image bearing member, for carrying a developer including toner and a carrier to a position where the developer carrying member is opposed to the image bearing member; a regulating member for regulating the amount of the developer to be carried on the developer carrying member; a driving device for rotating the developer carrying member; a controller for controlling the driving device to execute, at the time of end of image formation, a plurality of continuous operations each including acceleration of a rotational speed of the developer carrying member and deceleration thereof following the acceleration.

Abstract: A developing apparatus in which a first magnet of a first developing sleeve includes a first magnetic pole near a potion opposing to an image bearing member, and a second magnetic pole being downstream of the first magnetic pole; and a second magnet of a second developing sleeve includes a third magnetic pole near a portion opposing to the first sleeve. Assuming that a magnetic force obtained by combining normal direction forces Fr1 and Fr2 of magnetic forces generated by the first and second magnets, respectively, near the first sleeve is Fr, a center direction component of the first sleeve of the force Fr becomes positive between the first magnetic pole and a peak value position of the second magnetic pole, and a center direction component of the force Fr becomes negative between the peak value position and the closest position between both sleeves.

Abstract: A developing device uses a two-component developer including at least carriers and toners. The toners are supplied to an image bearing member bearing an electrostatic latent image so that a toner image is developed from the electrostatic latent image. The developing device has a developing roller arranged to oppose the image bearing member; and a magnetic roller arranged to oppose the developing roller. The magnetic roller retains the two-component developer to supply toners to the developing roller. The developing roller and the magnetic roller are rotationally driven in directions to be opposite from one another at an opposed position, and a magnetic pole of the magnetic roller and a magnetic pole of the developing roller have magnetic polarities different from one another at the opposed position. A surface roughness of the magnetic roller is greater than a surface roughness of the developing roller.

Abstract: An image forming apparatus has a photoconductive member, and a developing roller develops a latent image on the photoconductive member by a first alternating-current bias in the form of a rectangular wave. The following relationships are satisfied in calculating the duty ratio (D1) of the first alternating-current bias using an application period of voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: a CV value in the number particle size distribution of the toner is ?25%, 4 ?m?Dt?7 ?m, 105 ?·cm?pv?109 ?·cm, 0.4 ?m?Ra?1.5 ?m, and 35%?D1?75%. where Dt denotes the volume average particle diameter of the toner, pv denotes the intrinsic resistance value of a developing roller surface, Ra denotes the arithmetic average roughness of the developing roller surface.

Abstract: To downsize a developing device in the developing carrier axial direction without generating image concentration irregularities from recirculation of developer in the magnetic roller end regions, an N2 pole and an N3 pole, which are mutually adjacent having the same polarity (N polarity), and which are for generating a magnetic force for removing from a developing sleeve a developer that has passed through a developing region, are provided on a magnetic roller. Magnets of this developing device, which are for generating a magnetic field to displace to the inside in the axial direction magnetic force lines that cause peeling force in the direction of separation from the developing sleeve to act on developer on the developing sleeve, based on the magnetic force of the N2 pole and the N3 pole, and that pass through the axial direction end regions within a developer separation region on the developing sleeve, are provided on the outside of the magnetic roller.

Abstract: A developer station for an electrographic printer is provided that reduces developer agitation. The developer station includes a sump of magnetic developer, and a magnetic brush roller mounted above said sump and having a rotatable magnetic core surrounded by a substantially cylindrical toning shell rotatably mounted with respect to the core. The toning shell defines a nip at its closest point to the photoconductor element. A toning shell and magnetic core radius along with the eccentric offset of the toning shell from the rotating magnetic core are used in combination with the magnetic properties of the rotating magnetic core to determine the radius of the toning shell and magnetic core to improve the skiving and removal of developer from the toning shell after the developer has passed through the nip with the photoconductor element.

Abstract: A developer station and method for an eletrographic printer is provided that reduces developer agitation. The developer station includes a sump of magnetic developer, and a magnetic brush roller mounted above said sump and having a rotatable magnetic core surrounded by a substantially cylindrical toning shell rotatably mounted with respect to the core. The toning shell defines a nip at its closest point to the photoconductor element. A tangent line tangent to the cylindrical toning shell at the nip is oriented substantially vertically, and the magnetic developer is applied to the toning shell at an angular distance of no more than about 120° from said nip. The toning shell may be eccentrically mounted with respect to the magnetic core and is substantially closest to the rotatable magnetic core within about +30° and ?30° from said nip. Such a configuration advantageously reduces the residence time of the developer on the toning shell.

Abstract: The carrier includes a particulate core material having magnetism; and a resin layer located on the surface of the particulate core material. The resin layer is prepared by forming a layer including a copolymer, which includes a unit (A) having a specific acrylic siloxane structure, a unit (B) having a specific acrylic silicone structure having a crosslinking ability, and a unit (C) having a specific acrylic structure in a specific ratio, on the particulate core material, and then subjecting the layer to a heat treatment to crosslink the layer.

Abstract: A developing apparatus using a two-component developer constituted by a magnetic carrier and a toner, and an image forming apparatus comprising the developing apparatus. A developing unit and a stirring unit are provided, and in order to suppress toner scattering that may occur after a development operation has been halted for a long time, and thereby suppress contamination of the apparatus interior, the developer in a developing machine is transferred to a stirrer serving as a developer storage unit on the exterior of the developing machine when the development operation ends.

Abstract: A development apparatus using a hopping method and an image formation apparatus including the development apparatus are disclosed. The development apparatus includes a toner supporting object for supporting and conveying a toner by a movement of the toner supporting object, while the toner is hopping on a surface of the toner supporting object by an electric field; a regulating member made of a flexible material for constituting a toner thickness regulation position; a latent image supporting object for supporting a latent image; and a development position, which is a position of the toner supporting object, that counters the latent image supporting object; wherein the toner is conveyed through the regulation position to the development position where the toner is adhered to the latent image, and wherein one end of the regulating member is supported, and the other end contacts the toner supporting object.

Abstract: A developing apparatus includes a non-magnetic sleeve installing a magnetic field creating device, a developer carrier that carries and conveys developer including magnetic carrier and toner, and a development casing that contains developer. The development casing includes an opening that allows the developer carrier to be partially exposed and oppose a latent image carrier. The surface of the developer carrier vertically moves in the opening. An angle (?) between an inner wall surface of the development casing, located in the vicinity of opening on the down stream side and the horizontal plane, meets the following relation, wherein ? represents a static friction coefficient of the inner wall surface in relation to the toner; Sin ?>?×cos ?.

Abstract: A developing device includes a developing roller and a blade. The developing roller includes: a developing sleeve which rotates while holding two-component developer composed of toner and magnetic carrier on the outer surface having a plurality of grooves extending in parallel to an axis of the rotation; and a magnetic member, provided inside the developing sleeve in such a manner as to be unrotatable, for attracting the two-component developer onto the outer surface of the developing sleeve. The blade is provided outside the rotating sleeve with a gap from the outer surface of the developing sleeve for scraping off a part of the two-component developer on the outer surface of the developing sleeve. Also, the magnetic member includes a magnet for controlling magnetic flux density in the gap to range from 70 mT to 150 mT. This allows preventing image degradation caused by generation of development memory.

Abstract: An image forming apparatus including: an image bearing member; and a developer bearing member bearing a developer including a toner and a carrier, the developer bearing member developing an electrostatic image formed on the image bearing member with the developer, and the developer bearing member being applied with an alternate voltage in order to form an alternate electric field between the developer bearing member and the image bearing member, wherein assuming that electric field intensities Eb and Ed be Eb=|(Vp1?VL)/D| and Ed=|(Vp2?VL)/D|, a relationship, 0?K1>K2, is satisfied, where K1: a gradient at Ed, and K2: a gradient at Eb, and wherein a resistivity ?b of the carrier at the electric field intensity Eb satisfies 1.1×106×en<?b<6.0×107 [?·m] (where: e is the base of natural logarithms; and n=4×Eb×10?7).

Abstract: An electrostatic image developer contains a toner and a carrier having a resin coating layer formed on the surface of a core material containing a ferrite component, wherein a ratio R1/R2 is from 0.88 to 0.92 where R1 is the resistance value (?) of the developer having a toner concentration of 2 mass % in a state formed into a magnetic brush, at an applied voltage of 104 V/cm, and R2 is the resistance value (?) of the developer having a toner concentration of 12 mass % in a state formed into a magnetic brush, at an applied voltage of 104 V/cm.

Abstract: An image forming apparatus includes an image carrier that carries a latent image; a charging device that charges the image carrier with a charging voltage having an AC component; and a roller that carries a developer to be supplied to the image carrier in a developing position, with a surface of the roller provided with axially-formed grooves, the frequency of the AC component of the charging voltage and the number of the grooves provided on the roller being set so that non-uniformity in density of an output image becomes invisible, caused by interference between the frequency of the AC component of the charging voltage and the frequency at which the grooves pass the developing position.

Abstract: An image forming apparatus and process cartridge which uses a two-component developer comprising a toner and a carrier. By using toner and carrier having a small-particle size, deterioration of the toner fluidity over time can be avoided, and further by maintaining stable toner charge even in a low-humidity environment, stable high-quality image formation can be achieved. The occurrence of adherence of carrier to the solid portions of the toner image is reduced in addition to the occurrence of adherence of carrier to the edge portions, and image abnormalities, toner scattering and the like are prevented.

Abstract: In a configuration with a plurality of developing units, an influx of air into one developing unit from another developing unit can be blocked with a simple configuration. An operation section for a developing unit that is not in operation rotates a developer roll in the reverse direction to move developer accumulated on a pickoff pole, and fills a clearance formed between a housing and the developer roll with the developer so that the air flow of the developing unit that is not in operation is blocked. Accordingly, even if a difference in pressure between a developing unit that is in operation and a developing unit that is not in operation occurs, an air flow from the developing unit in operation to the developing unit not in operation is not apt to be formed, and an influx of air into the developing unit that is not in operation is blocked.

Abstract: A developing device and an image forming apparatus capable of restraining density irregularity and restraining a decline in image quality caused by adherence of carrier to a photoreceptor, are provided. An angle ? is in a range of no less than 45 degrees nor more than 57 degrees, which is formed between a plane comprising a central line of magnetic pole formed by a regulating pole in a magnet roller and a rotating central axis of a developing sleeve and a plane comprising a central line of magnetic pole formed by a pumping pole and a rotating central axis of the developing sleeve. Further, an absolute value of the maximum value of strength of the magnetic pole formed by a main pole is in a range of no less than 120 mT nor more than 140 mT.

Abstract: An image forming apparatus including an image bearer, a magnetic field generator, a two-component developer bearer, a developing electric field generator, and an image developer. The two-component developer has at least a current speed index (25FRI) of from 0 to 2.0, which is determined by the following formula: 25FRI=(total energy at 10 mm/s/total energy at 100 mm/s). The total energy is an integral sum of a rotary torque and a vertical load when a blade of a powder fluidity analyzer spirally rotates at 10 mm/s and 100 mm/s, respectively, in the developer having a volume of 25 ml after idly agitated in the image developer for 10 minutes.

Abstract: A developing apparatus in which a first magnet of a first developing sleeve includes a first magnetic pole near a potion opposing to an image bearing member, and a second magnetic pole being downstream of the first magnetic pole; and a second magnet of a second developing sleeve includes a third magnetic pole near a portion opposing to the first sleeve. Assuming that a magnetic force obtained by combining normal direction forces Fr1 and Fr2 of magnetic forces generated by the first and second magnets, respectively, near the first sleeve is Fr, a center direction component of the first sleeve of the force Fr becomes positive between the first magnetic pole and a peak value position of the second magnetic pole, and a center direction component of the force Fr becomes negative between the peak value position and the closest position between both sleeves.

Abstract: A developer includes a developer carrying body that carries a two-component developer having a magnetic toner and a carrier. A toner carrying body opposes the developer carrying body and receives toner from the developer carrying body. An image carrying body develops an electrostatic latent image by toner carried on the toner carrying body. A first magnetic member is inside the developer carrying body and opposes a surface of the toner carrying body. A second magnetic member is inside the toner carrying body and opposes the surface of the developer carrying body. The second magnetic member is magnetized to an opposite polarity to the first magnetic member and generates a magnetic force at least on the surface of the toner carrying body in a range of 25 mT to 40 mT in a direction perpendicular to the surface of the toner carrying body.

Abstract: A developing apparatus including a first development sleeve carrying a developer toward a first development area, a second development sleeve carrying the developer from the first sleeve toward a second development area, a first magnet roller disposed in the first sleeve and having a first magnetic pole, a second magnet roller disposed in the second sleeve and having a second magnetic pole, a first magnet member disposed in the vicinity of an axial end of the first sleeve without facing the first magnetic pole, and a second magnet member disposed in the vicinity of an axial end of the second sleeve without facing the second magnetic pole. A surface facing the second sleeve in an end area downstream of the second magnet member in a rotating direction of the second developer carrying member is identical in polarity with the second magnetic pole.

Abstract: In accordance with an embodiment of the embodiment of the invention, an image forming apparatus includes: an electrostatic image-bearing member; and a developing device. The developing device includes a developer-carrying member disposed to face the electrostatic image-bearing member, and a developer carried on the developer-carrying member. The developer includes a carrier having a volume-average particle size dc (?m) and a toner having a volume-average particle size dt (?m) of at most 5 ?m and contained at a weight ratio C with respect to the carrier of from 5 to 10% and is controlled so as to provide a surface coverage F of the carrier with the toner of from 30 to 80% as calculated according to Formula (I): F=(¼)×(dc/dt)×(pc/pt)×C, wherein pc denotes a true specific gravity (?) of the carrier, pt denotes a toner absolute specific gravity (?), and C denotes a weight ratio (?) of the toner to the carrier.

Abstract: A first carrying member supplies a developer to a developer carrier at the position of a developer attracting magnetic pole H4 while longitudinally carrying the developer, and a second carrying member carries the developer released from the developer carrier at the position of a developer releasing magnetic pole H3. The developer carrier 13a has two magnetic poles H2 and H4 of the same polarity sandwiching the developer releasing magnetic pole H3. Moreover, the developer releasing magnetic pole H3 is formed by the two magnetic poles H2 and H4 so that the polarity of the developer releasing magnetic pole H3 differs from the polarity of the two magnetic poles H2 and H4.

Abstract: A magnetic polymer particle develops a magnetic latent image. The magnetic polymer particle includes a magnetic component, a polymer, and a colorant. The magnetic component is a magnetic particle containing iron having a number average particle diameter of from about 0.2 ?m to about 1.2 ?m. The magnetic particle is contained in one magnetic polymer particle in an amount of from 1 to 10 particles. The number average particle diameter of the magnetic polymer particle is from about 2.0 ?m to about 7.0 ?m.

Abstract: A magnetic roller includes a cylindrical magnetic field generation part (140), a cylindrical support part (143) that contacts both of the edges of the magnetic field generation part (140), further has a smaller diameter than the magnetic field generation part (140), and which is installed upon a common axis thereof as an axis of the cylindrical support part (143), and a depression part (140c) that is installed upon an obverse surface of the cylindrical magnetic field generation part (140), extends in a direction of the axis of the magnetic field generation part (140), and wherein a lengthwise magnet formation is inserted.

Abstract: A developing unit for an image forming apparatus including an agent carrying member, a supply compartment, a supply screw, a recovery compartment, a recovery screw, an agitation compartment, and an agitation screw. The agent carrying member carries and supplies developing agent to an image carrying member. The supply screw in the supply compartment supplies the developing agent to the agent carrying member. The recovery screw in the recovery compartment, provided under the agent carrying member, transports the developing agent dropped from the agent carrying member. The agitation screw in the agitation compartment receives the developing agent from the supply compartment and recovery compartment, and transports the developing agent to the supply compartment. The recovery compartment, supply compartment, and agitation compartment are provided side-by-side in a horizontal direction. A magnetic flux density in a given area of the agent carrying member is set to 10 mT or less.

Abstract: An image forming apparatus is disclosed. The image forming apparatus includes a photosensitive body, a magnetic roller disposed at a predetermined distance from the photosensitive body, and a donor roller disposed between the photosensitive body and the magnetic roller. The donor roller has a diameter larger than the closest distance between the photosensitive body and the magnetic roller. The image forming apparatus includes gap rings and pressing device to maintain desired gaps between the magnetic roller and the donor roller and between the donor roller and the photosensitive body.

Abstract: The invention relates generally to processes for electrographic image development. An electrographic development apparatus is provided wherein a film is adjacent a cylindrical toning shell and a mixture of toner and carrier is particles disposed on the cylindrical toning shell in contact with the film. The cylindrical toning shell is closest to the film at a first location, the mixture of toner and carrier particles being movable through the first location with a flow direction. A magnetic core disposed within the cylindrical toning shell offset toward the cylindrical shell such that a magnetic field strength is greater at the second location than the first location.

Abstract: A developing unit includes a developing hopper for storing a dual-component developer. In the developing hopper, an opening portion is formed at the position opposing the outer peripheral surface of a photoreceptor drum. A developing roller for supplying the developer to the photoreceptor drum to develop an electrostatic latent image is provided inside the developing hopper. The developing roller has a multi-pole magnetic member having a multiple magnetic poles and a non-magnetic sleeve. The multi-pole magnetic member has a multiple number of magnetic poles radially arranged apart from each other. The photoreceptor drum incorporates an opposing magnetic pole formed of a bar magnet having a rectangular section, disposed at a position opposing the magnetic pole across a photosensitive layer. The opposing magnetic pole has a polarity dissimilar to that of the main magnetic pole.

Abstract: In a method or system where inking in an electrophotographic printer or copier, a magnetic roller is provided having a rotatable magnetic roller sleeve having a circumferential surface to which a two-component mixture comprising toner particles and ferro-magnetic carrier particles adheres. An applicator element has a circumferential surface to be inked with toner particles and past which the two-component mixture adhering to the circumferential surface of the magnetic roller is guided to produce a toner layer on the applicator element. The magnetic roller has a magnetic rotor which comprises magnetic elements and arranged inside the magnetic roller sleeve. A magnetic rotor and the magnetic roller sleeve are moveable relative to one another.

Abstract: An apparatus and method for managing magnetic carrier in an electrostatographic printer including an apparatus for directing magnetic carrier from the photoconductor, back toward the feed apparatus wherein the apparatus includes a magnetic carrier scavenger such that there is more magnetic carrier volume in the direction of the feed apparatus as well as a well to collect any magnetic carrier that does not move toward the feed apparatus.

Abstract: A developing device is provided with a developer accommodating vessel accommodating developer having as primary components a nonmagnetic toner and magnetic particles referred to as a carrier. The carrier is composed of a magnetic material as a core material that is uniformly covered with an insulating synthetic resin. The toner is mixed with the carrier at a weight ratio to the overall weight of the developer of 3-10%. The carrier has an average particle size of 65 ?m or less and a saturation magnetization of at least 70 emu/g. The developing device includes a developing roller and a sleeve roller that rotates about the developing roller. The surface of the sleeve roller is processed with metal shot to achieve a surface roughness of 0.45-1.08 times the average particle size of the carrier, or more specifically a roughness Rz of about 30 ?m.

Abstract: An image forming apparatus capable of collecting residual toner from the donor roller by means of a plurality of magnetic rollers and consequently, reducing the occurrences of possible ghost phenomenon caused by the toner residue. The image forming apparatus includes an image receiving member having an electrostatic latent image formed on a surface thereof, a donor roller to receive a toner and form a layer of toner on an outer circumferential surface thereof, the donor roller being arranged to oppose the image receiving member so as to develop with toner the electrostatic latent image of the image receiving member, and a plurality of magnetic rollers each to support magnetic brushes of carrier.

Abstract: In an image forming apparatus provided with an organic photoreceptor; a developing device to bring a developing brush in contact with the organic photoreceptor so as to visualize an electrostatic latent image to toner image; a transfer device; and an agent supplying device to provide a surface energy lowering agent to the surface of the organic photoreceptor. The electrostatic latent image is visualized to the toner image while the developing sleeve is rotated in a direction counter to that of the organic photoreceptor at the developing section.

Abstract: A two-component developer including toner and magnetic carriers is provided. The two-component developer is characterized in that when a development device including a developer bearing member bearing the two-component developer is operated under a development condition of an image forming apparatus using a quasi-photoconductor in which a 10 ?m thick layer of tetrafluoroethylene resin is provided to a conductive material, the number of times of light emission occurring in a magnetic brush formed on the developer bearing member due to partial conduction in the magnetic brush is 10 times or less per second at an observation cross section that is perpendicular relative to a rotation axis of the developer bearing member.

Abstract: An image forming apparatus and process cartridge which uses a two-component developer comprising a toner and a carrier. By using toner and carrier having a small-particle size, deterioration of the toner fluidity over time can be avoided, and further by maintaining stable toner charge even in a low-humidity environment, stable high-quality image formation can be achieved. The occurrence of adherence of carrier to the solid portions of the toner image is reduced in addition to the occurrence of adherence of carrier to the edge portions, and image abnormalities, toner scattering and the like are prevented.

Abstract: It is an object of the present invention to provide a process unit and an image forming apparatus in which generation of loss of image density due to flying off of developer and the edge effect occurring as a side-effect under developing conditions aimed at improving development performance can be reduced, even when a DC bias development system is adopted, and which can suppress developing density unevenness caused by impact occurring on contact of the teeth of gears in the drive system.

Abstract: A developing apparatus, a process cartridge and an image forming apparatus which form an image whose image density can be maintained, which form a fogged image and which form an image of uneven density within an acceptable range, even when the diameter of a developer carrying member is not more than 12 mm. The apparatus includes a developer carrying member whose outer diameter is in the range of 8 mm to 12 mm, and a magnetic mono-component developer 43 having a saturation magnetization of in a range of 20 Am2/kg to 37 Am2/kg when the magnetic field of 79.6 kA/m (1000 oersteds) is applied, the magnetization of not less than 70% and not more than 80% of the saturation magnetization when the magnetic field is lowered to 55.7 kA/m (700 oersteds), and the magnetization of not less than 50% and not more than 62% of the saturation magnetization when the magnetic field is lowered to 39.8 kA/m (500 oersteds).

Abstract: A specific magnet roll design for high speed semi-conductive magnetic brush (SCMB) development systems for magnetic image character recognition (MICR) printing is provided. The resulting magnetic field distributions include a more uniform radial field and enhance solid area development and halftone graininess without or substantially without bead carryout issues. In addition, this enhancement of solid area development enables magnetic toner in these hill speed SCMB systems that normally would not provide sufficient development latitude for MICR.

Abstract: An improved development station extends the useful life of toner in the housing and increases the number of images developed by the developer supply. The improved development station includes a development station housing having a developer sump, a toner supply for providing toner material to the developer sump, a mixing auger for uniformly blending and charging toner particles provided by the toner supply into developer material, a magnetic roller for receiving the developer material and bringing the developer material into contact with a photoreceptive member, and a magnet for generating a varying magnetic field to restrict flow of the developer material in the development station housing.

Abstract: An image forming apparatus having an image carrier for forming an electrostatic latent image and a developing unit for developing the electrostatic latent image with a two-component developing agent, the developing unit includes: a developing agent carrier for developing the electrostatic latent image to form a visible image, having inside thereof a development main magnetic pole for forming a bristle of a magnetic brush; and a plurality of magnetic poles for conveying the developing agent, wherein the developing unit performs a counter type contact developing method, and wherein, the development area is formed so that, a contact width of the bristle of the magnetic brush is 70% or less with respect to a development width, and a center position of the contact width is positioned on an upstream side with respect to a center position of the development width in a rotation direction of said image carrier.

Abstract: A developing method including forming a magnetic brush of a two component developer comprising a toner and a magnetic carrier; and developing an electrostatic latent image with the magnetic brush, wherein the ratio (Anc/At) of the area (Anc) of the carrier-noncontact portion to the area of the development portion in which the electrostatic latent image can be developed by the magnetic brush is from 0.30 to 0.70, and the ratio (Avc/vs) of the average moving velocity (Avc) of carrier particles contacting the image bearing member to the moving velocity (vs) of the surface of the developer bearing member is from 0.8 to 1.1. Alternatively, it is possible that the ratio (Anc/At) is not greater than 0.50 and the ratio (Avc/vs) is from 0.3 to 1.1.

Abstract: In a color image forming apparatus comprising a plurality of developing devices each provided with a developing roller structured with a developing sleeve and a fixed magnetic pole member, an agitating member, a recovering and feeding member, a regulating member and a developing device casing member, at least one of the plurality of developing devices has a different developer storing capacity and a different outer diameter of the recovering and feeding member for the other developing devices and has the same angle allocation values among the plurality of fixed magnetic poles in the fixed magnetic pole member.

Abstract: An electrostatic image developer contains a toner and a carrier having a resin coating layer formed on the surface of a core material containing a ferrite component, wherein a ratio R1/R2 is from 0.88 to 0.92 where R1 is the resistance value (?) of the developer having a toner concentration of 2 mass % in a state formed into a magnetic brush, at an applied voltage of 104 V/cm, and R2 is the resistance value (?) of the developer having a toner concentration of 12 mass % in a state formed into a magnetic brush, at an applied voltage of 104 V/cm.

Abstract: An image forming apparatus includes a latent image carrying member, a two-component developer carrying member holding on an outer surface a developer containing carrier beads and toner particles, the two-component developer carrying member having a first magnetic element mounted therein, a toner carrying member carrying a thin toner layer on an outer surface, a toner collecting roller for collecting the toner particles scattered and suspended in the vicinity of the two-component developer carrying member and the toner carrying member, the toner collecting roller having a second magnetic element mounted therein, and a housing accommodating the two-component developer carrying member, the toner carrying member and the toner collecting roller. The toner collecting roller is located face to face with the two-component developer carrying member with the first and second magnetic elements disposed to face each other with oppositely directed polarities.

Abstract: An image forming apparatus includes a main frame having a first driving force transmitting part, and a first electrode to supply power, a developing cartridge mounted to the main frame, and having a second driving force transmitting part engaged to the first driving force transmitting part to receive a driving force, and a second electrode electrically connected with the first electrode, and a pressing member disposed to the main frame to regulate a widthwise direction movement of the developing cartridge mounted to the main frame to guide an engagement between the first and second driving force transmitting parts, and an electrical connection between the first and second electrodes.

Abstract: An image forming apparatus having a photoconductive drum to form an electrostatic latent image corresponding to a predetermined image by a laser beam scanned after being electrified to a predetermined electric potential, and a developing roller to rotate together with the photoconductive drum having a developing gap therebetween and to transfer a developer, which is a mixture of a toner and a carrier, to the photoconductive drum to form a toner image on the electrostatic latent image, wherein a linear velocity ratio of a linear velocity of the developing roller to a linear velocity of the photoconductive drum is provided at a predetermined ratio, which provides maximum quality of the toner image.

Abstract: An image forming method, includes: forming a latent electrostatic image on a latent electrostatic image carrier; developing the latent electrostatic image with a toner to thereby form a visible image; transferring the visible image to a recording medium; and fixing the image transferred to the recording medium. The latent electrostatic image carrier includes: a support, a photoconductive layer on the support, and a surface protective layer on the support. The surface protective layer includes a reactant made by cross-linking the following: an electric charge transporting material which comprises a reactive functional group, a cross-linking resin, and a fluorine surfactant. The toner comprises an inorganic fine particle which defines an effective inorganic fine particle amount in a range of 0.8% by mass to 3.