Abstract: A developing device includes a developing container, a developing roller, a supplying roller, a first magnetic including a first magnetic pole, a second magnetic including second to fifth magnetic poles, and a regulating member. Maximum magnetic flux densities of the third and fourth magnetic poles are larger than maximum magnetic flux densities of the fourth and fifth magnetic poles, respectively, with respect to a normal direction to the supplying roller. In a case that positions where a magnetic flux density of the fourth magnetic pole is 50% of the maximum magnetic flux density thereof with respect to the normal direction are a first position and a second position, a position where the magnetic flux density of the fourth magnetic pole becomes maximum with respect to the normal direction is downstream of an intermediary position between the first position and the second position by 3 degrees or more.

Abstract: An image forming apparatus includes a main assembly, a first cartridge including an image bearing member, a second cartridge including a developing member, a developer supplying member provided in the second cartridge, and a controller for changing a polarity of a developer supply amount control bias which is a difference between the developing bias and the developer supplying bias depending on a print ratio based on an inputted image data. The controller changes the polarity of the developer supply amount control bias depending on at least one of a use history of the first cartridge and a use history of the second cartridge and on the print ratio.

Abstract: An image forming apparatus comprising: an image forming unit including a containing unit; a replenishment unit replenishes the containing unit with the toner; a first determination unit determines an amount of the toner consumed in the containing unit; a detection unit detects a toner amount in the containing unit; a first calculation unit calculates a difference between the toner amount and a target amount; a second calculation unit calculates a cumulative value of the difference; a second determination unit determines a determination value; a prevention unit prevents the second calculation unit from accumulating the difference at second timing following the first timing; and a controller controls the replenishment unit, based on the determination value, in a case where the first determination value is less than a threshold, the second calculating unit is prevented from accumulating the difference at the second timing, on the cumulative value calculated at the first timing.

Abstract: An image forming apparatus comprising: an image forming unit including a containing unit; a replenishment unit replenishes the containing unit with the toner; a first determination unit determines an amount of the toner consumed in the containing unit; a detection unit detects a toner amount in the containing unit; a first calculation unit calculates a difference between the toner amount and a target amount; a second calculation unit calculates a cumulative value of the difference; a second determination unit determines a determination value; a prevention unit prevents the second calculation unit from accumulating the difference at second timing following the first timing; and a controller controls the replenishment unit, based on the determination value, in a case where the first determination value is less than a threshold, the second calculating unit is prevented from accumulating the difference at the second timing, on the cumulative value calculated at the first timing.

Abstract: An image forming apparatus has a first voltage application section for applying a first bias to a magnetic roller, a second voltage application section for applying a second bias to a developing roller, and a controller for controlling the voltages of the first and second voltage application sections and the driving/rotating of the magnetic roller and the developing roller. When no image formation is taking place, the controller can execute a toner collection mode in which, with the first and second biases set at the same potential and the second bias set lower than the voltage applied to an image carrying member, the magnetic roller is rotated in the direction reverse to that in which it is rotated during image formation.

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 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: A developing device includes a developer supporting rotator, toner supporting rotator and voltage application unit. The toner supporting rotator is arranged opposite to a developer supporting rotator, supports toner supplied from the developer supporting rotator, and forms a toner layer by a magnetic brush. The voltage application unit causes the toner supported by the toner supporting rotator to an electrostatic latent image on a surface of an image carrier to develop it into a toner image. A longitudinal end portion of the toner supporting side magnetic member is positioned longitudinally more outside than a longitudinal end portion of the developer supporting side magnetic member. A surface of the second rotating sleeve positioned more outside than the end of the developer supporting side magnetic member is composed of a surface of low adherence with lower toner adherence and a higher dielectric constant than those of a surface positioned inside thereof.

Abstract: A development device includes: a developer carrier that is positioned to oppose an electrostatic latent image carrier and that supplies a developer to the electrostatic latent image carrier; a developer supply member that is positioned to oppose the developer carrier and that supplies the developer to the developer carrier; a developer charging member that is positioned to oppose the developer supply member and that charges the developer.

Abstract: A development system (10) for an electrophotographic printer (100) with multiple augers and containing a development roller (11) and a first channel (12) containing a feed auger (13) and developer (14), where the magnetic strength of the feed pole of the development roller increases in the direction of developer flow (18) in the first channel. This increase in magnetic field strength of the feed pole (50) ensures that a uniform layer of developer is formed on the development roller despite the volume of developer in the first channel decreasing along the length of the first channel in the direction of developer flow.

Abstract: Provided are a development apparatus and an image forming apparatus which, in a hybrid development apparatus provided with a plurality of toner carriers, a toner supply capability to supply toner to each toner carrier is controlled independent of development electric fields between the toner carriers and an image carrier, whereby each toner carrier is allowed to exhibit a desired development capability, and even in the case of high speed development, a high quality image is provided. The phases, the frequencies, and/or the duty ratios of the alternating current components of the voltages applied to the plurality of the toner carriers are made to be different, whereby the toner supply amount for each toner carrier from the developer carrier is controlled independently of the development electric fields between the toner carriers and the image carrier.

Abstract: Provided is a development device and an image forming apparatus both using a hybrid development method and capable of forming high quality images without occurrence of development hysteresis (ghost). The nip portion of the toner carrier and the developer carrier is configured as follows: the rotating direction of a toner carrier and a developer carrier are in counter directions; a magnetic pole facing the toner carrier is positioned on the upstream side in the developer carrier rotating direction; and a counter charge generated by the toner supply reaches a toner recovering portion without being considerably attenuated.

Abstract: A developing unit includes a brush member that includes a base member and a plurality of raisings that are erected on a surface of the base. The brush member traps toner within the raisings and causes a flicker movement in the raisings of the brush so that the toner trapped within the raisings is shaken and flown due to the flicker movement to the surface of a toner carrying member.

Abstract: A developing device is provided with a developing roller arranged to face a photoconductor for forming an electrostatic latent image and adapted to supply a toner to the photoconductor, an agitating member for agitating a developer, a supply roller that holds the developer agitated by the agitating member, and supplies the toner to an area facing the developing roller; a restricting member for blocking the developer supplied onto the supply roller and restricting the amount of the developer conveyed by the supply roller, and an intermediate roller including a first magnetic pole facing in a direction toward the staying developer by being restricted by the restricting member for attracting the staying developer and arranged at such a position as to face the developer blocked by the restricting member. Thus, the developing device can avoid image quality deterioration even when a developing process continues over a long period of time.

Abstract: A developer supply device, comprising: a carrying substrate having electrodes arranged along a developer transport path at predetermined intervals to carry a developer through a traveling electric field, wherein the carrying substrate comprises: a rigid upper carrying substrate formed to stand to carry the developer upward; and a flexible bottom carrying substrate curved to be a semispherical shape and is configured to charge the developer by friction with the developer and to be connected with a lower end portion of the upper carrying substrate so as to form a bottom surface of a developer reservoir portion, and wherein a joint portion of the bottom carrying substrate connected to the lower end portion is overlapped with the lower end portion such that the joint portion carries the developer in a same direction as a direction in which the developer is carried by the lower end portion.

Abstract: A developing apparatus usable with an image forming apparatus includes a developer carrier includes a plurality of magnetic poles and a case to rotatably support the developer carrier, the case storing developer is supplied to the developer carrier, and a magnetic pole changing apparatus disposed at an end of the developer carrier to change a position of the plurality of magnetic poles with respect to the case.

Abstract: In accordance with the invention, there are printing apparatuses and methods of forming an image. An exemplary printing apparatus can include a fuser subsystem including one or more light induced heating elements, each of the one or more light induced heating elements including plurality of nanomaterials, wherein the nanomaterials are selected from the group consisting of carbon nanotubes and metal nanoshells. The exemplary printing apparatus can also include one or more light sources disposed in close proximity to the one or more light induced heating elements, each of the one or more light sources having an emission in the absorption range of the plurality of nanomaterials and disposed to produce heat in the fuser subsystem by light absorption by the plurality of nanomaterials.

Abstract: A development device includes a developing roller composed of an elastic body. An intermediate roller made of metal is disposed closely to the developing roller so as to face the developing roller. A magnetic roller is disposed closely to the intermediate roller so as to face the intermediate roller. A developer layer composed of a magnetic carrier and a toner is formed on the surface of the magnetic roller. The developer layer is carried to the intermediate roller side, and only the toner in the developer layer is transferred to the intermediate roller. A toner layer formed thus is transferred from the intermediate roller to the developing roller, and brought into contact with the surface of an image carrying member.

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: A developing device is disclosed that is capable of preventing the hysteresis phenomenon, and which contains a toner and a carrier. The toner and the carrier are charged to different polarities by frictional contact thereof. The developing device has a first conveyance member and a second conveyance member which faces an electrostatic latent image bearing body via the second region. An electric field forming device forms a first electric field between the first conveyance member and the second conveyance member to move the toner in the developer retained by the first conveyance member to the second conveyance member, and forms a second electric field between the second conveyance member and the electrostatic latent image bearing body to move the toner retained by the second conveyance member to an electrostatic latent image of the electrostatic latent image bearing body.

Abstract: Provided are a developing device and an image forming apparatus, the developing device which employs a two-component developer wherein development hysteresis (ghost) is reduced and deterioration of a carrier is stably suppressed, and high-quality images are thus realized for a long period of time. The developing device, which uses a developer including toner, carrier and reverse polarity particles which are charged to have a polarity reverse to that of the toner, performs a collecting operation for collecting the reverse polarity particles at a timing in which image formation is not affected by a collecting operation, where the reverse polarity particles are accumulated in the area enclosed by a toner carrying member, a developer carrying member for toner supply and developer carrying member for collecting toner are collected into a developer container.

Abstract: There is provided an image formation device, comprising: a holding body configured to hold thereon developer and to have a center axis extending in a main scanning direction; and a developer supply unit configured to supply the developer to the holding body through a traveling electric field, the developer supply unit having an opening through which a part of the holding body is accommodated in the developer supply unit. In this configuration, the developer supply unit comprises a sliding member configured to slide on at least a part of a surface of the holding body moving toward an outside of the developer supply unit through the opening.

Abstract: A developing apparatus is provided which can suppress a fluctuation in image density in a discontinuous printing mode provided with a pause period. The developing apparatus includes a developer for developing an electrostatic latent image on a photosensitive drum, a developer bearing member for carrying and conveying the developer and a developer layer thickness-regulating unit placed close to the developer bearing member for regulating the amount of the developer carried and conveyed by the developer bearing member, the developer layer thickness-regulating unit being. As the developer, a negatively chargeable, one-component, magnetic toner is used having magnetic toner particles containing a binder resin and a magnetic iron oxide particle, and has a specific saturation magnetization, specific weight-average particle diameter and specific composition.

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 image forming apparatus has a photoconductive member on which a latent image is to be formed, a developing roller for developing the latent image on the photoconductive member by a first bias. A magnetic roller forms a magnetic brush thereon with a two-component developer and forms a thin toner layer on the developing roller by a second bias. The developing roller is aluminum with a surface treated for high resistance. The thickness (T) of the toner layer and the duty ratio (D1) of the first alternating-current bias satisfy relationships of the following equations for calculating the duty ratio (D1) using an application period of a voltage in a direction to transfer the toner from the developing roller towards the photoconductive member as a positive period: 7 ?m?T?13 ?m, and 35%?D1?70%.

Abstract: In a development apparatus of the hybrid method using a component developer, a development apparatus and a development method are provided that prevent the reduction of density or the occurrence of residual images (ghost images) and can carry out good image forming over a long period of time. A development apparatus has the feature that the surfaces of the toner supporting member and the developer supporting member move in a mutually opposite direction at the part where they are opposite to each others. The development apparatus further employs an electric field in the closest part applied in a direction to recover the toner from the toner supporting member to the developing supporting member, wherein the magnitude of the electric field is in the range from 2.5×106 V/m to 5×106 V/m. The developer of the development apparatus is such that its share (PD) in the space of the closest part of the opposing portion satisfies the following relationship: 0.09?PD?650×Dss.

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 uses a two-component developer containing a toner and a carrier. The apparatus has a latent image bearer for bearing an electrostatic latent image. A toner bearer bears the toner to be conveyed to a development region to develop the electrostatic latent image. A developer bearer bears the two-component developer and supplies the toner to the toner bearer. A regulator sets the thickness of a toner layer carried on the toner bearer to 6 ?m to 15 ?m and sets a difference between a half width of a first toner charge number distribution as a number distribution of the charge amount of the toner carried on the toner bearer and that of a second toner charge number distribution as a number distribution of the charge amount of the toner in the two-component developer carried on the developer bearer to 0.8 (10?10 C/m) or smaller.

Abstract: A developing roller includes (I) a developing sleeve that is made of nonmagnetic material, and that holds and conveys a developer; and (II) a magnetic member that is fixed inside the developing sleeve, wherein the magnetic member includes (i) a development magnetic pole that corresponds to a development area; (ii) a before-development magnetic pole that is provided at an upstream side of the developer-conveying direction with respect to the development magnetic pole, and that has a polarity different from the development magnetic pole; and (iii) an after-development magnetic pole that is provided at a downstream side of the developer-conveying direction with respect to the development magnetic pole, and that has a polarity different from the development magnetic pole, wherein q1, q2 and q3 satisfy the following formulas q1>90°; and q1+q2>q3, wherein q1, q2 and q3 are defined in the specification.

Abstract: In the image forming apparatus by: visualizing an electrostatic latent image formed on an electrostatic charge carrying member; transferring a toner image, which is thus visualized, to a recording medium, or to a recording medium through an intermediate transfer material; and fixing the toner image, which is thus transferred to the recording medium, to obtain a recorded image, the toner includes at least a fixing resin, a colorant, a releasing agent, and an external additive, the toner has an average particle diameter in a range of from 4 to 12 ?m and including no particle having a diameter of 45 ?m or more, a ratio of a toner adhesion amount in a character part to a toner adhesion amount in a solid image part upon printing is more than 0.5 and less than 4, and the toner adhesion amount in a character part is 1.6 mg/cm2 or less.

Abstract: A hybrid type developing apparatus and method forms a magnetic brush of non-magnetic toner and a magnetic carrier on a circumference of a magnetic roller forms a uniform toner layer on the circumference of a donor roller using only toner from the magnetic roller, and develops an electrostatic latent image on an image receptor. The hybrid type developing apparatus includes: a plurality of electrodes on the circumference of the donor roller; first and second brush electrodes in an upstream area and a downstream area, respectively, of the donor roller facing the magnetic roller with respect to a direction of rotation; and a bias applying device for applying a recovery bias to the first brush electrode to remove toner from the donor roller and a supply bias to the second brush electrode to supply toner from the magnetic roller to the donor roller.

Abstract: A developer apparatus for a printing device includes a rotatable developer carrying member which carries developer thereon. A magnet assembly is disposed in the developer carrying member. The magnet assembly includes a plurality of magnets for conveying the developer. The magnets generate a magnetic field over a larger proportion of a circumference of the developer carrying member in an edge region adjacent an end of the developer carrying member than in a mid-region longitudinally spaced from the end of the member by the edge region. The apparatus enables unwanted toner emissions to be reduced by the development of a stable annular magnetic brush in the edge regions.

Abstract: The toner of the present invention is suitably used in SLIC development system where a liner velocity of a developer-bearing member is 150 to 500 cm/sec. The toner has resin particles containing at least a coloring agent, and a charge controlling agent fine articles, and a ratio M/T of the amount M (% by weight) of an element in the surface of toner particles as determined by X-ray photoelectron spectroscopy (XPS) to the amount T (% by weight) of the element in the entire toner particles of 20 to 500, which element is present only in a charge control agent among components of the toner and is an element belonging to one of the first, second, third, fourth, and fifth periods of the long form of periodic table of elements except hydrogen, carbon, oxygen, and rare gas elements.

Abstract: The toner of the present invention is suitably used in SLIC development system where a liner velocity of a developer-bearing member is 150 to 500 cm/sec. The toner has resin particles containing at least a coloring agent, and a charge controlling agent fine articles, and a ratio M/T of the amount M (% by weight) of an element in the surface of toner particles as determined by X-ray photoelectron spectroscopy (XPS) to the amount T (% by weight) of the element in the entire toner particles of 20 to 500, which element is present only in a charge control agent among components of the toner and is an element belonging to one of the first, second, third, fourth, and fifth periods of the long form of periodic table of elements except hydrogen, carbon, oxygen, and rare gas elements.

Abstract: To control bending of a magnetic field generation unit provided inside a developer carrying member, a developing apparatus for developing an electrostatic image formed on an image bearing member according to the present invention includes: a developer container which contains a magnetic developer; first and second developer carrying members which carry the developer in the developer container to the image bearing member; and first and second magnetic field generation units which are fixedly arranged in the first and second developer carrying members. In the developing apparatus, the first magnetic field generation unit and the second magnetic field generation unit form a magnetic field for delivering the developer from the first developer carrying member to the second developer carrying member, and the developing apparatus further includes a magnetic unit which exerts a magnetic force, which resists a magnetic force caused by the magnetic field, on the first and second magnetic field generation units.

Abstract: An image forming apparatus of non-contact developing method using two-component developer material which is capable of obtaining a clear image free from fogging, ghost and toner contamination. The image forming apparatus has at least one developing unit which includes a developing roll and a magnetic roll, the developing unit develops an electrostatic latent image on a photosensitive body with a toner thin layer formed on the surface of a developing roll wherein a toner thin layer forming region on the developing roll is smaller than a magnetic brush forming region on the magnetic roll. A high resistivity region is adjacent each end of the toner thin layer forming region on the developing roll. A control device controls a developer material replenishment and controls the biasing to the developing roll and magnetic roll.

Abstract: In order to provide an image forming apparatus capable of forming a quality image by restricting a distance between a developing roll and a magnetic roll with a simple structure, an image forming apparatus comprises a magnetic roll 1 and a developing roll 2 that are disposed in parallel with a predetermined distance and a developing unit 50 that develops an electrostatic latent image on a photosensitive body drum 3 disposed on the image forming apparatus main body using a toner thin layer formed on the surface of the developing roll by the magnetic roll, wherein a member for holding rotational axes having a pair of openings for holding, which fits and holds rotatably and integrally each of rotational axes of the magnetic roll and the developing roll is provided, the opening for holding of the developing roll being capable of swinging around the axis center of the opening for holding of the magnetic roll.

Abstract: To avoid developing ghost and selective developing without complicating a developing apparatus and to supply surly charged toner to a developing roll while unevenness of images is not generated to obtain stable images for a long time even when continuous printing, a method for developing in a hybrid developing apparatus is provided, which is characterized in that a data amount of each image, which an image forming apparatus prints and a number of paper sheets passed are detected and that an interval of the action of recovering and exchanging a toner layer on the developing roll to the magnetic roll after printing between paper sheets is variably set in accordance with a printing coefficient determined by the data amount and the number of paper sheets passed and further, a method for developing in a color tandem-type image forming apparatus provided with a plurality of the hybrid developing apparatuses for all different colors of toner, which are disposed along the moving direction of a transfer medium of imag

Abstract: A method and apparatus for image forming includes a hybrid developing apparatus that supplies surly charged toner to a developing roll. The apparatus includes a developing roll that is electrically conductive at least on its surface. The image forming apparatus and the method have a constitution capable of applying an alternating current bias having a duty ratio in the range of 10 to 50% and a direct current bias superposed thereon. The developing roll is directly confronted with a latent image bearing body through an insulative toner thin layer at the nearest region of the developing roll and the latent image bearing body. An independent bias is applied to each of the developing roll and the magnetic roll, and the toner is refreshed by the varying duty ratio of the alternate current bias and the direct current bias after developing.

Abstract: The development is performed under a condition that |Q2|−|Q1|/|Q1≦±0.45. Here, Q1 denotes an average amount of charge on toner held on a development roller and carried toward a development region immediately before development. Q2 denotes an average amount of charge on toner immediately before development held and carried toward the development region in the state immediately after development of an electrostatic latent image on a development drum. This is effective to allow the amount of charge q/m on toner held on the development roller to have a variation rate of 45% or below and an afterimage rate R within 2%.

Abstract: A developing device for an image forming apparatus of the type feeding a one-ingredient or two-ingredient type developer, forming a thin toner layer on a developing roller or toner support member and developing a latent image with the toner layer is disclosed. The toner support member has a surface that is chargeable to the same polarity as toner. The toner support member therefore serves to simply support the toner without electrostatically effecting the toner, so that the development of a latent image is free from the influence of the static electricity of the toner support member. This successfully enhances image quality. A photoconductive element has a coefficient of friction &mgr; confined in the range of 0.1<&mgr;<0.4, preventing the toner from depositing on and contaminating the background area of the element. In addition, the surface of the photoconductive element is protected and has its service life extended.

Abstract: A control unit is configured in such a manner that at a transition from a developing state to a non-developing state both of DC and AC components of a development bias that are superimposed on each other are instantaneously interrupted after the duty factor of the portion of the AC component having the opposite polarity to the developer charging polarity is gradually increased.

Abstract: A development roller for use in a machine in which marking particles are advanced toward a latent image to form a developed image is provided. The development roller includes a conductive body. The conductive body includes a central portion, a peripheral portion spaced from the central portion, and a support structure interconnecting the peripheral portion to the central portion. The development roller also includes a semiconductive material applied to an outer periphery of the conductive body.

Abstract: In a developing device comprising a developing member for transferring toner onto an electrostatic latent image for visualization, and a developer supplying member for magnetically attracting two-component developer on the peripheral surface for conveyance, and supplying two-component developer or toner to the developing member, the developer will be sufficiently agitated on the developer supplying member, and toner density and amount of toner charge in the two-component developer will be controlled with simple structure. A part of two-component developer, to which toner has been supplied on the developer supplying member, is caused to flow back on the upstream side in the conveying direction within a range in which the attracting force of magnetic poles of the internal member which the developer supplying member has acts.

Abstract: An electrophotographic developing apparatus uses a two-component developer comprising a carrier and a toner for development. The apparatus includes an intermediate roller with a non-magnetic sleeve accommodating a magnetic roller disposed between a developing roller and an agitating device for tribo-frictionally charging the carrier and the toner. After forming a magnetic brush consisting of the carrier and the toner, the toner is transferred to the developing roller by applying a first bias to the intermediate roller and the developing roller. A second bias is applied to the developing roller and an image carrier included in the apparatus to cause the toner to selectively attach to the image carrier. A third bias is applied to the developing roller and the intermediate roller to cause the toner to transfer back to the intermediate roller.

Abstract: Developing device (3A) for use in an electrophotographic image forming apparatus such as copy machine includes a developer material (31) having toner particles (37) and carrier particles (39) and a housing (5) for containing the developer material. The housing includes a developer bearing member (21) and a toner bearing member (9) to form a give-and-take region (23) through which the toner particles are transferred to and from the developer bearing member. A packing density in the give-and-take region is equal to or more than 29.5%. The packing density is defined by the following equation:P.D=100?M/(D.rho.)!whereinP.D: Packing density (%)M: Amount of developer material per unit area on first developer member (mg/cm.sup.2)D: Distance between developer and toner bearing members (cm).rho.: Unit weight of developing material (g/cm.sup.3).

Abstract: A developing device includes a developing sleeve for carrying a magnetic developer, a regulating sleeve for regulating the thickness of the layer of the developer on the developing sleeve, magnets for generating a magnetic field in a layer-thickness regulating portion by the regulating sleeve, and magnetic members provided so as to have a small gap between the circumferences of the developing sleeve and the regulating sleeve. Leakage of the developer from end portions is prevented by forming a magnetic seal by way of a magnetic field between each of the magnetic members, and between the regulating sleeve and the developing sleeve.

Abstract: In a developing apparatus, a developing roller has a toner layer formed on a surface thereof, which toner layer is brought into contact with a photoconductor. A magnetic conveying roller having a magnet body is arranged rotatively close to the photoconductor. A regulating plate is provided at an outer periphery of the conveying roller.

Abstract: In a developing unit used for an image forming apparatus to develop an electrostatic latent image on an image carrier, there are provided a developing agent carrying member for carrying a developing agent, a magnet roll disposed in the developing agent carrying member and a supporting member for supporting the magnet roll. A portion of the supporting member is melted so that a central shaft of the magnet roll is welded to the supporting member to attain fixation between the magnet roll and the supporting member.

Abstract: In an image forming apparatus, a developing device operable with toner or single component type developer has a hard first developing roller and a soft second developing roller. Fine magnetic N-S poles are formed on the periphery of the first roller. The second roller conveys the toner, electrostatically transferred thereto from the first roller, to an image carrier. The device frees a toner image from deterioration due to toner particles charged to a polarity opposite to an expected polarity. The toner forms a uniform thin layer on the first roller and is uniformly charged. Toner for use with this type of developing device is also disclosed.