Abstract: A transfer unit that transfers a developing agent image formed with a developing agent, includes a belt; and a rotational body that stretches the belt. The rotational body includes a shaft body, and a surface layer provided on an outer side of the shaft body in radial directions. Surface roughness of an outer peripheral surface of the surface layer is greater than a volume mean particle diameter of the developing agent.

Abstract: A developing device includes a transporting member that transports a developer in an axial direction while rotating, a developing unit that hands over the developer to an image holder, on which an electrostatic latent image is formed, while rotating, and develops the electrostatic latent image, a pumping unit that has a rotation member rotating in a circumferential direction, pumps the developer transported by the transporting member with a magnetic force, and supplies the pumped developer to the developing unit by releasing the developer in a tangential direction of the rotating rotation member, and a changing unit that changes a flowing direction of the developer, which is released in the tangential direction of the rotating rotation member and is to be supplied to the developing unit.

Abstract: A developing device including a developing sleeve installed in a developing chamber and partially exposed to an outside of the developing chamber through an opening portion, a magnetic member located inside a developing sleeve and including a separating pole and a receiving pole, the separating pole being located on a downstream side of the opening portion based on a rotating direction of the developing sleeve to separate a developing agent from the developing sleeve, and the receiving pole being located on a downstream side of the separating pole to attach the developing agent to the developing sleeve, and a magnet located between an inner wall of the developing chamber and the magnetic member to face a region between the separating pole and the receiving pole and having same magnetic polarity same as the separating pole and the receiving pole.

Abstract: A fixing method of fixing a regulating blade made of a resin to a mounting portion of a developing frame made of a resin so that the regulating blade is in non-contact with a developer carrying member, the fixing method including: imaging the mounting portion; determining a target value of a gap between the developer carrying member and the regulating blade based on characteristic information of a shape of the imaged mounting portion; giving, to the regulating blade, a force for deflecting the regulating blade to adjust a relative position of the regulating blade with respect to the developer carrying member that the gap falls within a predetermined range including the target value over a longitudinal direction of the developer carrying member; and fixing the regulating blade to the mounting portion in a state in which the regulating blade has been deflected and the gap falls within the predetermined range.

Abstract: A developing device includes a hardware processor that performs control not to cause an image to be formed on an image bearing member by a first developer bearing member and to cause a first image to be formed on the image beating member by a second developer bearing member, in which the hardware processor corrects developing conditions of the plural developer bearing members based on a developability detection result of the first image formed by the second developer bearing member.

Abstract: A developing device includes: an image bearing member; a plurality of developing rollers each supplying toner to the image bearing member, and developing an electrostatic latent image on the image bearing member into a toner image; and a hardware processor analyzing values representing density fluctuations during the toner being supplied from the developing rollers to the image bearing member, for the respective developing rollers, and correcting a control value for an image density of at least one developing roller among the developing rollers based on an result of the analyzing so as to eliminate the density fluctuations, in consideration of an effect caused at the developing roller on a downstream side in a rotational direction of the image bearing member by correcting the control value for the image density of the developing roller on an upstream side.

Abstract: A development device includes: a developer carrier including a magnet roller and a sleeve around the magnet roller; and a restriction member provided opposed to the sleeve surface. When a region on the surface opposed to the restriction member is defined as a first region and regions adjacent to the first region are defined as second and third regions, a magnetic flux density is largest in the second region. When a position where the density is largest in the second region is defined as a reference position, a position where the density is a predetermined value in the second region is defined as a downstream position, and a position where the density is the predetermined value in the third region is defined as an upstream position, the width between the reference position and the upstream position is longer than the width between the reference position and the downstream position.

Abstract: A developing device includes a first developing roller, a second developing roller, a first end portion configured to restrict the amount of developer on the second developing roller, a restriction member, and a collecting roller configured to collect developer on the first developing roller. The second end portion is located at a position where magnetic force interference with a magnetic force generated by the second developing roller and the collecting roller is not caused.

Abstract: A magnetic carrier comprising: a magnetic material-dispersed resin carrier core material; and a resin coating layer on the surface of the magnetic material-dispersed resin carrier core material, wherein the magnetic material-dispersed resin carrier core material contains a core material particle containing a magnetic material and a binder resin, and a primer compound having an amino group, the resin coating layer contains a coating resin A, which is a polymer of monomers including at least a (meth)acrylic acid ester having an alicyclic hydrocarbon group, and the content of the primer compound in the magnetic material-dispersed resin carrier core material and the content of the resin coating layer are in specific range.

Abstract: An image forming apparatus includes an image bearing member and a developing device having a first developer bearing member and a second developer bearing member, disposed with a gap therebetween. A controller executes a mode in which a first difference between an amplitude of an alternating current bias of a first developing bias applied to the first developer bearing member and an amplitude of an alternating current bias of a second developing bias applied to the second developer bearing member at a time of non-image formation is set to be large compared to a second difference between an amplitude of the alternating current bias of the first developing bias applied to the first developer bearing member and an amplitude of the alternating current bias of the second developing bias applied the second developer bearing member at a time of image formation.

Abstract: An image forming apparatus includes a belt, a plurality of image forming devices including a photosensitive member, a developing device, a transfer device and a blade, and a control device configured to form a pattern image on a first photosensitive member, when an image to be printed on a sheet is not formed, by applying a developing voltage to a first developing device, an absolute value thereof is greater than that when an image to be printed on a sheet is formed, transfer the pattern image onto the belt and apply a transfer voltage or transfer current having the same polarity as that applied to a second transfer device when an image to be printed on a sheet is formed to the second transfer device when the pattern image to be conveyed by the belt passes the second transfer device.

Abstract: A developing apparatus includes a developer carrying member configured to carry a developer, and a magnet member disposed inside the developer carrying member. The magnet member includes one or more first magnet portions having a first magnetic polarity at an outer surface thereof opposing an inner surface of the developer carrying member, and one or more second magnet portions having a second magnetic polarity at an outer surface thereof opposing the inner surface. In a cross-section perpendicular to a longitudinal direction of the magnet member at a longitudinally central portion thereof, a number of the first magnet portions is larger than a number of the second magnet portions, and a ratio of a total area of the first magnet portions in the cross-section is smaller at a longitudinally end portion of the magnet member than at the longitudinally central portion.

Abstract: A development device including a plurality of development sleeves and conducting development sleeve end portion seal using magnet members, a second magnetic pole and a third magnetic pole of a magnet incorporated in a second developer bearing member form repulsive poles. A position on the magnet member facing a rotation direction downstream end of the second developer bearing member is configured to be included in a zero Gauss zone. As a result, developer leak in the development sleeve rotation direction from between two development sleeves is suppressed.

Abstract: A developing device includes a first magnet fixed inside a first developer bearing member and including a pair of first repulsion magnetic poles with the same polarity and disposed adjacent to each other, and a second magnet fixed inside a second developer bearing member and including a pair of second repulsion magnetic poles with the same polarity and disposed adjacent to each other. The first magnet has a magnetic flux density distribution of a normal component of the first developer bearing member in the circumferential direction of the first developer bearing member having only one minimal point between the pair of first repulsion magnetic poles, and the second magnet has a magnetic flux density distribution of a normal component of the second developer bearing member in the circumferential direction of the second developer bearing member having a plurality of minimal points between the pair of second repulsion magnetic poles.

Abstract: In an image forming apparatus, a coating layer of each of a photoconductor drum and a collecting roller has been formed by a dipping method in which a base body of each of the photoconductor drum and the collecting roller is dipped in a liquid in a state where the base body is in a vertical attitude such that a first end of the base body faces down and a second end of the base body faces up. The collecting roller is supported in a state where the first end of the collecting roller base body and the second end of the drum base body face a same direction.

Abstract: An image forming apparatus includes a rotatable photoconductor and a developing device that uses a developer that exhibits magnetism, the developing device including a housing having an opening for development at a position facing the photoconductor, and plural developing rollers that are exposed through the opening in the housing, that rotate without contacting a surface of the photoconductor, and that are arranged without contacting each other in a direction in which the surface of the photoconductor rotates, wherein a minimum distance between an inner surface portion extending to the opening of the housing of the developing device and one of the developing rollers arranged close to the inner surface portion and a minimum distance between the housing and the surface of the photoconductor are each equal to or larger than a minimum distance between the developing rollers.

Abstract: A developing apparatus includes a developing container for containing a developer; a rotatable developer carrying member provided at the position of the developing container opposed to an image bearing member and configured to carry the developer into a developing zone where the developer carrying member is opposed to the image bearing member; and a guiding portion provided opposed to a carrying region, with respect to an axial direction of the developer carrying member, where the developer carrying member carries the developer, in a side of the developing container remote from the image bearing member, the guiding portion being capable of guiding the developer from an end portion of the developer carrying member with rotation of the developer carrying member.

Abstract: An image forming apparatus includes a photosensitive member, a first developer carrying member for carrying a developer comprising toner and a carrier for developing an electrostatic image formed on the photosensitive member, and a second developer carrying member for carrying the developer received from the first developer carrying. The second developer carrying member is disposed downstream of the first developer carrying member with respect to a rotational direction of the photosensitive member. In addition, a voltage source applies a developing bias voltage to the first developer carrying member and second developer carrying member, and a driving device rotates the first developer carrying member at a peripheral speed higher than that of the photosensitive member and rotates the second developer carrying member at a peripheral speed which is higher than that of the photosensitive member and which is lower than that of the first developer carrying member.

Abstract: A developing device including a first developer holding member disposed opposite to an image holding member that holds an electrostatic latent image, a second developer holding member, disposed opposite to the image holding member and the first developer holding member, a developer supply mechanism that supplies a developer to a position located further downstream than a development area in a direction of rotation of the second developer holding member and located further upstream than opposite locations of the two developer holding members, a regulation member that regulates the developer supplied by the developer supply mechanism, a developer division unit that divides the developer, supplied from the developer supply mechanism into two parts for the two developer holding members, and a developer carrying unit that holds and carries the developer after division toward the development area in a state where the developer is separated.

Abstract: A developing device includes a first developing roller including a first transport member that transports magnetic developer by rotating while being close to a latent-image carrier rotating in one direction and a first magnet member, a second developing roller including a second transport member that transports the developer by rotating while being close to the latent-image carrier at a position on a downstream side of the first developing roller in the one direction, and a second magnet member, and a regulation member that regulates transport amounts of the developer distributed to the first and second developing rollers to required transport amounts, and opposes the developing rollers with predetermined distances therebetween. The first and second developing rollers are spaced from each other. The regulation member is movably supported in an area closer to the latent-image carrier than a closest position between the first and second developing rollers.

Abstract: A developing device includes a first developing roller, a second developing roller, a layer regulation member, a pair of division magnetic poles that divide a developer which is held by the second developing roller after passing through the layer regulation member and transfer the developer to the first developing roller, and a transfer amount regulation member that has a plate shape, is provided in a developer transfer path formed by the pair of division magnetic poles between the first developing roller and the second developing roller so as to extend in an axial direction of the first and second developing rollers, and is provided with a slit which regulates the amount of developer passing therethrough.

Abstract: A developing device includes a container; a cylindrical first developer-transporting member rotatably supported by the container and whose rotation axis is substantially parallel with a rotation axis of a subjected-to-development member; a first magnet disposed inside the first developer-transporting member and secured to the container; a swinging member supported so as to be capable of swinging relative to the container around the rotation axis of the first developer-transporting member; a cylindrical second developer-transporting member at least one end portion of which is rotatably supported by the swinging member, the second developer-transporting member being adjacent to the first developer-transporting member and rotating in the circumferential direction to transport the developer to the subjected-to-development member; and a second magnet disposed inside the second developer-transporting member and secured to the swinging member.

Abstract: An inclined angle that an upstream surface of each groove in an upstream developing sleeve forms with the surface of the upstream developing sleeve is set smaller than an inclined angle that an upstream surface of each groove in a downstream developing sleeve forms with the surface of the downstream developing sleeve. This configuration increases a difference in transfer power between the upstream and downstream developing sleeves, thereby enabling the upstream developing sleeve to transfer a developer to the downstream developing sleeve efficiently.

Abstract: A developing device includes two developer-transporting members, a container, and four gap retainers. The container contains a developer and rotatably supports rotation shafts of the developer-transporting members using side walls located on both end portions. The gap retainers are supported at end portions of the developer-transporting members and are brought into contact with a subjected-to-development member or a supporter to maintain a gap between the subjected-to-development member and each developer-transporting member. A force with which the two developer-transporting members are pressed toward the subjected-to-development member is applied to the container and all the gap retainers are brought into contact with the subjected-to-development member or the supporter, while axes of rotation of the two developer-transporting members are allowed to become non-parallel with an axis of rotation of the subjected-to-development member.

Abstract: Provided is a developing device including a pair of developer holding members that include a pair of cylinder members, which are disposed close to each other and rotate in the same direction at an adjacent gap at which both cylinder members are in close proximity, and a pair of magnetic force generation sections which are provided inside the pair of cylinder members respectively and generate magnetic forces for holding a developer on the cylinder members, and a pair of developing magnetic poles that are provided in the pair of magnetic force generation sections respectively, are disposed to be opposed to a latent image holding member, and are set to have the same polarity.

Abstract: A developing device includes a first developing unit, a second developing unit, a rotating member, a magnetic pole forming member, a first separating pole, a second separating pole, a developer supplying unit, and a path formation member. The developing device is provided with a magnetic structure, in which, when a value of a magnetic flux density at which the developer is separated is a reference separation value, at a side of the first separating pole at the separation area of the second developing unit, a position where a magnetic flux density of a vertical component of a magnetic force becomes less than or equal to the reference separation value is disposed downstream in the direction of rotation of the rotating member of a position where a magnetic flux density of a horizontal component of the magnetic force becomes less than or equal to the reference separation value.

Abstract: An image forming apparatus includes an supporting an image bearing member; a developing unit including first and second developer carrying members for developing an electrostatic latent image formed on the image baring member; first and second gap regulating members for regulating gaps between the image bearing member and the first and second developer carrying members, respectively; an urging member for urging the developing unit toward the image forming unit; and a positioning member for positioning the developing unit relative to the image forming unit. The positioning member includes a preventing portion for preventing, while permitting movement of the developing unit in a circumferential direction of the image bearing member at one longitudinal end of the developing unit, movement of the developing unit in the circumferential direction of the image bearing member at the other longitudinal end of the developing unit.

Abstract: A developing device includes: a first developer carrier that is moved in a same direction as a moving direction of a latent image carrier at a faster linear speed than the latent image carrier; a second developer carrier that further develops the obtained toner image and that is moved in a same direction at a faster linear speed than the latent image carrier; and a bias output unit that outputs a developing bias to be applied to the second developer carrier. The developing bias includes a direct-current component and a non-rectangular alternating-current component whose waveform has a gentle edge at which a direction of an electric field between the second developer carrier and a background portion of the latent image carrier is changed to a direction in which the toner is moved from the background portion toward the second developer carrier.

Abstract: An electrostatic image developer includes a toner containing an external additive having a volume-average particle size of about 80 to 400 nm and an average circularity of about 0.7 to 0.85. The developer is used in an image forming apparatus including an image-carrying member having a top surface layer containing fluorocarbon resin particles, and a developer-carrying member that faces the image-carrying member and carries an electrostatic image developer, in which a value obtained by dividing the amount of developer on the developer-carrying member [g/m2] by a shortest distance between the image-carrying member and the developer-carrying member [?m] is about 0.8 to 1.8, and a peripheral velocity ratio of the developer-carrying member to the image-carrying member is about 1.5 to 5.0 or the developer-carrying member moves in a direction opposite to the image-carrying member in a facing portion.

Abstract: A developing device includes first and second developing rollers, a trimmer, a divider, and a movement regulator. The first and second developing rollers are arranged so as to face an outer peripheral surface of a photoconductor at downstream and upstream positions, respectively, in a rotation direction of the photoconductor, and respectively include first and second sleeves and first and second magnets. The trimmer is arranged so as to face an outer peripheral surface of the first developing roller, and regulates formation of a layer of developer held by the first developing roller. The divider divides the developer regulated by the trimmer into developer that adheres to the first developing roller and developer that adheres to the second developing roller. The movement regulator is disposed between the trimmer and the divider and regulates movement of the developer held by the first developing roller before the developer is divided.

Abstract: A developing device includes: a first developing body that develops a developing agent image on a development surface using a developing agent; a second developing body that develops a developing agent image on the development surface using the developing agent; and a sealing member that is disposed between a region where a first delivery pole and a second delivery pole are opposed to each other and the development surface, and adjacently to the first developing body and the second developing body at distances so small that developing agents formed as magnetic brushes on a first conveyance pole and a second conveyance pole respectively can touch the sealing member to secure sealing to prevent the developing agent from leaking to the outside of a device body.

Abstract: An inclined angle that an upstream surface of each groove in an upstream developing sleeve forms with the surface of the upstream developing sleeve is set smaller than an inclined angle that an upstream surface of each groove in a downstream developing sleeve forms with the surface of the downstream developing sleeve. This configuration increases a difference in transfer power between the upstream and downstream developing sleeves, thereby enabling the upstream developing sleeve to transfer a developer to the downstream developing sleeve efficiently.

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: A developing device includes a developing container unit configured to contain and circulate a developer, and a plurality of developer carrying members each for carrying on its surface the developer for developing an electrostatic latent image on an image bearing member. The developer carrying member providing a largest difference in driving torque measured before and after being coated with a toner on its surface thereof is provided with a plurality of circumferentially spaced grooves, and the remaining developer carrying member has a blast-treated surface.

Abstract: A developing apparatus in which one sleeve is swingable includes a first magnetic field generating member inside a first developer bearing member, a second magnetic field generating member inside a second developer bearing member, and a positioning unit configured to perform positioning of a swinging connecting member in the peripheral direction or to perform positioning of the swinging connecting member in the peripheral direction through connection thereto.

Abstract: A developing device, includes a developer agitating member, an upstream side developing roller, and a downstream side developing roller; wherein a toner in a developer handed over from the upstream side developing roller to the downstream side developing roller has a volume average particle size larger than a volume average particle size of the toner in the developer conveyed by the upstream side developing roller to the facing position between the upstream side developing roller and a photoreceptor drum.

Abstract: A developing device includes a first developing member rotating such that a moving direction of a portion opposing the image carrier is opposite a moving direction of the image carrier. A second developing member is provided on a downstream side of the first developing member in a rotating direction of the image carrier rotating such that a moving direction of a portion opposing the image carrier is the same as the moving direction of the image carries. A distributing member is supported movably relative to a proximal portion where the first developing member is closest to the second developing member so as to distribute developer to the first and second developing members by contact with the developer, and a biasing member biases the distributing member upstream in the rotating direction of the first developing member.

Abstract: In a method to optimize transfer of a developer fluid on a printing substrate in an electrophoretic printing apparatus, a developer fluid containing at least carrier fluid and toner particles is used, the toner particles having sizes that are greater than diameters of capillaries in a surface of the printing substrate. The additive particles are added to the developer fluid before the transfer, sizes of the additive particles being selected such that the sizes are smaller at least in part in comparison to the diameters of the capillaries in the surface of the printing substrate.

Abstract: An image forming apparatus includes a subjected-to-development member; a first developer-transporting unit; a regulator that regulates the thickness of a developer; a second developer-transporting unit; a density detecting unit that detects center density and edge density of a developed image formed on the subjected-to-development member by the first developer-transporting unit and the second developer-transporting unit; a reference-image forming controller that forms a reference developed image on the subjected-to-development member by forming an electrostatic latent image having a uniform image density at a center position and an edge position; and a speed controller that increases rotation speed of the second developer-transporting unit as compared to the case of forming the reference developed image if the center density of the reference developed image detected by the density detecting unit is lower than the edge density.

Abstract: A developing device includes first and second developer carriers facing each other in a facing region, a regulating member that regulates a layer thickness of developer, and a separation member. The first and second developer carriers respectively include first and second magnetic members that are respectively magnetized with first and second facing magnetic poles having opposite polarities. The separation member separates the developer so that the developer is supplied toward the first and second developer carriers. The separation member is disposed such that distances between the separation member and the first and second developer carriers are the smallest in a region in which a magnitude of a combined magnetic field of the first and second magnetic poles locally decreases as compared with a case where at least one of the first and second developer carriers is independently disposed due to interaction between the first and second facing magnetic poles.

Abstract: Provided is a developing device including a pair of developer holding members that include a pair of cylinder members, which are disposed close to each other and rotate in the same direction at an adjacent gap at which both cylinder members are in close proximity, and a pair of magnetic force generation sections which are provided inside the pair of cylinder members respectively and generate magnetic forces for holding a developer on the cylinder members, and a pair of developing magnetic poles that are provided in the pair of magnetic force generation sections respectively, are disposed to be opposed to a latent image holding member, and are set to have the same polarity.

Abstract: There is provided a developing device including a first developing roller that is disposed to be rotatable with a desired distance set between the first developing roller and an outer circumferential surface of a rotatable latent image holding member, transports a developer onto an outer circumferential surface thereof while holding the developer by magnetic force, and has a substantially cylindrical shape, and a second developing roller that is disposed to be rotatable with desired distances set between the second developing roller and the respective outer circumferential surfaces of the corresponding latent image holding member and the corresponding first developing roller at a position on the downstream side of the first developing roller in a rotation direction of the latent image holding member, transports the developer onto an outer circumferential surface thereof while holding the developer by magnetic force, and has a substantially cylindrical shape.

Abstract: Provided is a developing device including a first developer holding member disposed opposite to an image holding member that holds an electrostatic latent image, a second developer holding member, disposed opposite to the image holding member and the first developer holding member, a developer supply mechanism that supplies the developer to a position located further downstream than the development area in a direction of rotation of the developer holding member and located further upstream than opposite locations of the two developer holding members, a regulation member that regulates the developer supplied by the developer supply mechanism, a developer division unit that divides the developer, supplied from the developer supply mechanism into two parts for the two developer holding members, and a developer carrying unit that holds and carries the developer after division toward each of the development areas in a state where the developer is separated.

Abstract: A developing device includes: a developing housing in which a developer is to be contained; a first developer carrier that is placed opposedly to an image carrier which is rotated while a latent image is formed on a surface of the image carrier, that is supported by the developing housing, and that is rotated while holding the developer on a surface of the first developer carrier; a second developer carrier that is supported movably with respect to the developing housing, that is opposed to the image carrier on an upstream or downstream side of the first developer carrier in a rotation direction of the image carrier, and that is rotated while holding the developer on a surface of the second developer carrier; and a coupling defined herein.

Abstract: A development apparatus is equipped with a first developing roller, developer supply section, a second developing roller, a developer removing part and a developer recovery section. The second developing roller is disposed on the downstream side of the first developing roller and above the first developing roller, to which the developer is delivered from the first developing roller by magnetic force. The developer supply section includes a developer circulation section and a first regulating member that regulates an amount of the developer. The developer recovered by the developer recovery section drops by gravity and is introduced into the developer circulation section.

Abstract: A developing device includes a first developing roller, a second developing roller, a layer regulation member, a pair of division magnetic poles that divide a developer which is held by the second developing roller after passing through the layer regulation member and transfer the developer to the first developing roller, and a transfer amount regulation member that has a plate shape, is provided in a developer transfer path formed by the pair of division magnetic poles between the first developing roller and the second developing roller so as to extend in an axial direction of the first and second developing rollers, and is provided with a slit which regulates the amount of developer passing therethrough.

Abstract: A developing device includes a first developing member that rotates in a manner such that a moving direction of a portion opposing the image carrier is opposite a moving direction of the image carrier, a second developing member provided on a downstream side of the first developing member in a rotating direction of the image carrier and rotates in a manner such that a moving direction of a portion opposing the image carrier is the same as the moving direction of the image carrier, a distributing member supported movably relative to a proximal portion where the first developing member is closest to the second developing member so as to distribute developer to the first and second developing members by contact with the developer, and an a biasing member that biases the distributing member upstream in the rotating direction of the first developing member.

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: An image forming apparatus includes a rotatable photoconductor and a developing device that uses a developer that exhibits magnetism, the developing device including a housing having an opening for development at a position facing the photoconductor, and plural developing rollers that are exposed through the opening in the housing, that rotate without contacting a surface of the photoconductor, and that are arranged without contacting each other in a direction in which the surface of the photoconductor rotates, wherein a minimum distance between an inner surface portion extending to the opening of the housing of the developing device and one of the developing rollers arranged close to the inner surface portion and a minimum distance between the housing and the surface of the photoconductor are each equal to or larger than a minimum distance between the developing rollers.

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.