Abstract: An improved image forming apparatus comprises a first developing unit comprising a photosensitive body. Also provided is a second developing unit including a developing roller which is moveably installed so that the developing roller selectively contacts the photosensitive body. A pressing member selectively presses the second developing unit. The developing roller contacts the photosensitive body during a developing process and separates from the photosensitive body after the developing process is finished.

Abstract: The present invention relates to an image forming apparatus comprising: an exposing means and a developing means. The developing means comprises a plurality of developing devices, a rotating member rotatable while supporting the plurality of the developing devices, and a driving means for the rotation drive of the rotating member for selectively moving the plurality of the developing devices to the developing position such that the driving means transmits driving force to the rotating member via a gear at a drive transmitting position. An angle ?e(°) formed by a straight line linking the rotation center of the rotating member and the drive transmitting position and the tangent of the image bearing member at an exposing position in the image bearing member moving direction satisfies the following relationship with the premise that an pressure angle of the gear is ?(°) and the image bearing member rotating direction is positive:????e??.

Abstract: According to an aspect of the present invention, there is provided a developing device including: a roller that develops an electric latent image formed on an image holding body; a chamber that stores a toner; a case that houses the roller and the chamber; a concave portion that is inwardly concaved from the case and that includes: a sidewall, a bottom, and a filling port formed in the bottom; and a first lid that closes the filling port.

Abstract: A developer includes a developer frame in which a developing agent is contained, a development roller that is rotatably disposed inside the developer frame. Coupling means couples the development roller to the developer frame. The coupling means includes a gear member that is rotatably mounted to the developer frame and engages a first gear disposed outside the developer to transfer a rotational force. A development roller end portion rotates with the gear member in the same direction about the same rotational shaft as the gear member. An image forming apparatus includes a photosensitive medium on which an electrostatic latent image corresponding to an image to be printed is formed through light scanning and the developer, which applies a developing agent to the photosensitive medium to develop the image into a visible image.

Abstract: The invention provides a toner for electrostatic image development having a binder resin containing a amorphous polyester resin and a crystalline polyester resin, and a coloring agent, and satisfying the following relationship (1): SP(L)>SP(H)>SP(C) ??(1) wherein SP(H) is the solubility parameter of a resin contained in an elution fraction F (0-10) from the beginning of elution of W1 until 10% of elution of W1 when W1 is the whole area of an elution curve on a gel permeation chromatograph measured for an acetone-soluble fraction; SP(L) is the solubility parameter of a resin contained in an elution fraction F (80-100) from 80% to 100% of the elution of W1; and SP(C) is the solubility parameter of the crystalline polyester resin.

Abstract: An image forming apparatus includes a developing unit to form an image using a developing agent on one side of a printing medium transported along a simplex printing path, a fixing unit to fix the developing agent on the printing medium, a discharging roller to discharge the printing medium that passes the fixing unit, and a first driving source to drive the developing unit, the fixing unit and the discharging roller.

Abstract: A developing unit includes a developer container that includes an opening and holds a developer; a first screw that stirs and conveys the developer, and that supplies the developer to a developing roller; a second screw that stirs the first developer, and that conveys the developer to a direction opposite to a direction to which the first screw conveys the developer; and a partition wall that partitions between the first screw and the second screw. The partition wall includes a guiding member that guides, to a position within a range in which rotation of the first conveying unit reaches, a part of the developer that is supplied to the developing roller and is returned after being used for development from the developing roller, and at least a part of the guiding member is an adhesion surface to which a sealing member for sealing the opening is adhered.

Abstract: A developer carrier is capable of stably charging a toner over a long term without change in physical surface shape and composition. The developer carrier has at least a substrate and resin coating layer formed on a surface of the substrate. The resin coating layer includes at least graphitized particles (i) with a degree of graphitization p(002) of 0.20 to 0.95 and an indentation hardness HUT [68] of 15 to 60 or graphitized particles (ii) with a degree of graphitization p(002) of 0.20 to 0.95 and an average circularity SF-1 of 0.64 or more.

Abstract: A toner including toner particles including a binder resin, and a modified layered inorganic material in which at least part of interlayer ions is replaced with an organic ion, and a fatty acid metal compound located on a surface of the toner particles; and an external additive located on the fatty acid metal compound, wherein the external additive is a material different from the fatty acid metal compound. An image forming apparatus including an image bearing member; a developing device configured to develop the electrostatic latent image with a developer including the toner; a transfer device; and a fixing device. A method for preparing the toner including dispersing or emulsifying a toner composition including a modified layered inorganic material to prepare toner particles; mixing a fatty acid metal compound with the toner particles; and second mixing the toner particles with an external additive.

Abstract: An image forming method of forming images on both sides of a recording sheet; comprising the steps of: fixing a first toner image on a first surface a recording sheet; and fixing a second toner image on a second surface of the recording sheet; wherein in two-component developer includes toner particles each containing a binder resin having a glass transition temperature Tg ° C. and a colorant and carrier particles in each on which magnetic powder is dispersed in a binder resin including a phenol formaldehyde obtained by a polymerization process, and the first toner image is fixed with first heat in such a way that the surface temperature of the first surface of the recording sheet is a temperature in a range of Tg ° C. or more and lower than 100° C.

Abstract: A developer system for developing an image in an electrophotographic printing machine, including: a developer housing having a toner sump containing developer material; a magnetic development member rotatably mounted in the housing for transferring toner particles to a latent image on the photoreceptive member in a development zone; a transport system for transporting developer material from the toner sump to the magnetic development member, the transport system includes: a mix/pump auger, disposed in a first auger channel, for mixing and circulating developer material along a first path within the first auger channel; a transport auger, adjacent to the mix/pump auger and disposed in a second auger channel, for circulating developer material along a second path within the second auger channel; a wall member disposed in between the mix/pump auger and the transport auger, the wall member having a first opening disposed near an inboard end of the housing and a second opening disposed near an outboard end of the

Abstract: An image forming method includes: forming an electrostatic latent image after charging an organic photoconductor; and developing the electrostatic latent image into a toner image by bringing a developer containing toner and a carrier having a weight average particle size (D4) of 20 to 50 ?m into contact with the organic photoconductor comprising a photosensitive layer and a protective layer which is provided when needed, a total thickness of the photosensitive layer and the protective layer being 5 to 15 ?m.

Abstract: A toner in form of aggregate of resin-containing particles is manufactured by aggregating the resin-containing particles which contain binder resin and the colorant, with the aid of an aggregate dispersant containing a polymer in which anionic polar groups are bonded to a main chain. To be specific, salt of divalent or higher valent metal is added to a slurry of the resin-containing particles so that a metal ion and the anionic polar group are bonded to each other, and a temperature of the slurry is increased so that a bond between the anionic polar group and a water molecule is broken. This decreases water-solubility of the polymer so that the resin-containing particles are aggregated.

Abstract: To provide an image forming apparatus, image forming method and process cartridge, which are excellent in low-temperature fixation properties, storage stability, durability and filming resistance, can reduce generation of odor, and are capable of forming an extremely high quality image. The apparatus includes: a latent electrostatic image bearing member; a charging unit; an exposing unit; a developing unit; a transferring unit; and a fixing unit; wherein the toner comprises a binder resin and coloring agent, and the binder resin comprises a polyester-based resin (A) and polyester-based resin (B) having a melting point at least 10° C. higher than that of the polyester-based resin (A), and at least one of the polyester-based resins (A) and (B) is a resin derived from a (meth)acrylic acid modified rosin and includes a polyester unit obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing a (meth)acrylic acid modified rosin.

Abstract: A toner, and an electrophotographic apparatus and an electrophotographic process cartridge using the toner are provided having excellent charge stability without adversely affecting electric properties of the toner even when used for a long period of time and having excellent image density stability without bringing about image deletion and blurring. The toner includes colored particles containing at least a binder resin and a colorant, and two or more external additives. At least one of the external additives includes hydrophobic treated mesoporous particles, and the mesoporous particles are inorganic particles of at least one type selected from the group consisting of silica, titanium oxide, alumina, cerium oxide, and strontium titanate.

Abstract: The present invention provides an image processing apparatus on which an image forming engine for forming a full-color image by using color materials corresponding to data of color tones on the basis of C (cyan), M (magenta), Y (yellow), and K (black) data is mounted. The image processing apparatus includes: a color converting component for converting R (red), G (green), and B (blue) data input from the outside to C(1), M(1), and Y(1) data which depends on a characteristic of the image forming engine; a lightness acquiring component for acquiring lightness from the C(1), M(1), and Y(1) data obtained by the conversion of the color converting component; a memory for storing a lightness-gray value characteristic table; a gray value reading component; a first arithmetic component for obtaining C(2), M(2), and Y(2) data; a K data generating component; and a second arithmetic component for calculating C, M, and Y.

Abstract: Prior to the execution of a printing operation, a print preparatory operation is conducted only on a priority developer cartridge out of the plurality of monochromatic developer cartridges mounted to the developing unit thereby bringing the cartridge into a printable state. Therefore, the print preparatory operation is completed when the print preparatory operation on one (equivalent to a “priority cartridge” of the invention) of the developer cartridges mounted to the developing unit is terminated. Hence, the apparatus may be placed in the printable state in a short time so that the print preparatory operation is prevented from compelling a user to wait needlessly long and that waiting time of a user may be shortened.

Abstract: In an image forming method in which a toner image, which is visualized via an electrostatic latent image formed on an electrophotographic photoreceptor, employing a developer incorporating toner, is transferred onto a recording material followed by fixing, and any residual toner remaining on the electrophotographic photoreceptor is removed, an image forming method in which an electrophotographic photoreceptor and a toner which satisfy specified requirements are employed and image formation is carried out while feeding a surface energy lowering agent from the developer onto the aforesaid electrophotographic photoreceptor, and an image forming apparatus employing the same.

Abstract: The apparatus is brought into a printable state by selecting one print preparatory process from first and second print preparatory processes and conducting the selected print preparatory process prior to the execution of the printing operation. That is, the printing operation by means of the cartridge is enabled by conducting a print preparatory process desired by a user. Specifically, the print preparatory process is selected and conducted according to the user's desire (to produce a large volume of prints, to reduce the length of time required to become printable, or such). Therefore, the monochromatic printing in the above specific color can be efficiently performed in a manner conforming to the user's desire.

Abstract: An image forming apparatus includes: an image carrying member, a toner feeding unit that forms a charged toner on a surface of the image carrying member, a toner image forming unit that forms a reversely charged toner image by applying charge to the charged toner according to image information, the applied charge having a polarity contrary to the charged toner, a color forming information applying unit that applies color forming information to the reversely charged toner image with light, a transferring unit that transfers the reversely charged toner image to a surface of a recording medium, a fixing unit that fixes the reversely charged toner image transferred to the surface of the recording medium, and a color forming unit that forms color of the toner image applied with the color forming information, the charged toner including a first component and a second component that are capable of forming the color upon reaction with each other, and are separated from each other in the toner, and a photo-curable com

Abstract: An image forming method including forming an image of a toner on a receiving material; and fixing the toner image on the receiving upon application of heat and pressure thereto, wherein the weight average particle diameter (D4) of the toner is from 2.0 to 4.5 ?m, the pressure (P) is not greater than 15 N/cm2, P×D4 is not less than 30 N/cm2·?m, the melt viscosity (Gw110) of the toner at 110° C. is from 3,000 to 40,000 Pa·s, the melt viscosity (Gw140) of the toner at 140° C. is from 100 to 1,000 Pa·s, and the ratio Gw110/Gw140 is not less than 30.

Abstract: An image forming apparatus including an image bearer; a charging device charging the image bearer; a light irradiating device irradiating the charged image bearer with light to form an electrostatic image; a developing device developing the electrostatic image with a developer including a toner to form a toner image on the image bearer; a transfer device transferring the toner image; and a cleaning device cleaning the image bearer, wherein the volume average particle diameter of the toner is greater than 5.0 ?m and less than 5.5 ?m, the content of toner particles having a particle diameter of not greater than 4.0 ?m is not higher than 20% by number, the ratio of the first shape factor SF-1 to the second shape factor SF-2 is from 1.00 to 1.15, and the content of toner particles having a SF-2 of not less than 115 is not less than 67.8% by number.

Abstract: The present invention discloses a cleaning patch and method thereof for cleaning a residual toner in a developing unit. The cleaning patch is composed of a plurality of cleaning regions. Each cleaning region includes a plurality of cleaning toner point alternately arranged in a row, which may reduce the absorbed toner in each cleaning region to improve the image quality.

Abstract: An image forming apparatus producing images at a speed of from 500 to 1,700 mm/sec, including an image bearer; a charger; an irradiator; an image developer developing an electrostatic latent image with a developer including a toner including a binder resin and a colorant; a transferer; a cleaner; and a fixer, wherein the binder resin includes a crystalline polyester resin and an amorphous resin, wherein a peak ratio (W/R) of a specific peak height (W) of the crystalline polyester resin to a specific peak height (R) of the amorphous resin is from 0.050 to 0.555, and a toner transfer rate T (%) determined by the following formula (1) is from 75 to 100%: T(%)=(V?A)×100/V ??(1) wherein V represents a toner volume (mg/cm2) of the toner image on the image bearer; and A represents a toner volume (mg/cm2) thereof remaining on the image bearer after transfer.

Abstract: A power transmitter, including a driving gear rotated by a driving motor, a driven gear rotatably coupled with the driving gear through a coupler, and a power interruption unit to be broken when the driven gear is overloaded so as to release the coupling between the driven gear and the coupler such that power transmission to the driven gear is cut off.

Abstract: The present invention is directed to an article, system and method for determining and/or selecting the location of a toner engaging member in a developing agent device such as a toner cartridge. The article, system and method may be applied to a printing device such as a laser printer.

Abstract: The developing agent is selected to have a distribution of adhesive force to the surface of an image carrier, which is configured such that the ratio of the developing agent having an adhesive force which is not less than 2.5 times as high as an average value of a distribution of adhesive force is 3% by weight or less based on an entire weight of the developing agent.

Abstract: A developing device is provided with: a developer containing section that is for containing a developer and that has a predetermined coefficient of thermal expansion; a developing roller for bearing the developer contained in the developer containing section; a roller-supporting member that is for rotatably supporting the developing roller, that has a coefficient of thermal expansion which is different from the coefficient of thermal expansion of the developer containing section, and that is structured by connecting at least three members; and a gap for preventing the roller-supporting member and the developer containing section from interfering with one another when the roller-supporting member and the developer containing section expand/contract due to a change in temperature.

Abstract: Disclosed are a developing device, a developing cartridge, a process cartridge, and an image forming apparatus in which image deficiency is prevented by absorbing the tolerance of each component and making the position of the developing roller in the thrust direction constant and which are easy to assemble. A frame member is equipped with an urging unit that axially urges the developing roller, the urging unit urging the developing roller in the direction of movement of the developing roller by the thrust force of a helical gear when a driving force is transmitted to the developing roller, to thereby make the position of the developing roller in the thrust direction constant.

Abstract: An image forming apparatus whereby it is possible to prevent unevenness in developing density caused by misalignment between the central axes of a driven side rotational coupling section for rotating a developer carrier and a drive side rotational coupling section for transmitting rotational drive force to the driven side rotational coupling section. The driven side rotational coupling section is fixed and the position thereof can be corrected slightly, by engaging the driven side rotational coupling section with a drive side rotational coupling section. A transmission gear is provided which meshes with the driven side rotational coupling section and transmits rotational drive force used to move the surface of the developer carrier. By means of an axle provided on at least one end of the transmission gear engaging with a positioning member on the main body of the image forming apparatus, the developer carrier is positioned in the main body of the image forming apparatus.

Abstract: The ratio of the particles of developing agent having a particle diameter of not more than A×0.5 (?m) (wherein A is a 50% average particle diameter (?m)) and the ratio of the particles of developing agent having a particle diameter of not less than A×1.5 (?m) (wherein A is a 50% average particle diameter (?m)) are both confined to not more than 5% by number in a number particle size distribution, the ratio of the developing agent having an adhesive strength of not more than 1.3×10?8(N) is confined to 10% by weight or less and the ratio of the developing agent having an adhesive strength of not less than 3×10?7(N) is confined to 5% by weight or less in a distribution of adhesive strength to the surface of the image carrier.

Abstract: A developing device including: a first developer carrying member for carrying a developer to develop a latent image formed on an image bearing member; a first regulating member, disposed on one end of a longitudinal direction of the image bearing member, for regulating a gap between the image bearing member and the first developer carrying member; a second developer carrying member for carrying a developer to develop the same latent image formed on the image bearing member; and a second regulating member, disposed on the one end of the longitudinal direction of the image bearing member, for regulating a gap between the image bearing member and the second developer carrying member, wherein the first and second regulating members are disposed without being superposed upon each other in the longitudinal direction.

Abstract: An image forming apparatus including an image bearing member bearing latent images; a developing unit including plural developing devices developing the latent images with developers to form visual images, each developing device including a developer bearing member bearing the developer to develop the latent image, and a developer thickness controlling member contacting the developer bearing member to control the thickness of a developer layer on the developer bearing member; and a driving device including at least one driving source, a forward rotation driving member rotated by the driving source to drive the developer bearing members to forwardly rotate to develop the latent images, and a reverse rotation driving member rotated by the driving source to drive the developer bearing members to reversely rotate when the developing operation is not performed, wherein the forward rotation driving member and the reverse rotation driving member can operate at the same time.

Abstract: A developing cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The cartridge includes a developing roller, for developing an electrostatic latent image formed on an electrophotographic photosensitive member, having an elastic roller portion and a shaft portion supporting the elastic roller portion, a developer regulating member; a protecting member including a contact portion provided for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member; and a supporting portion for supporting the contact portion and provided for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member. The contact portion has a hardness which is not less than a predetermined value and not more than a hardness of the elastic roller portion.

Abstract: Toner particles are described containing at least one toner resin and at least one wax. The wax present in the toner particles has an average domain size of about 1 micron or less. Developer systems, two component and monocomponent, are further described as well development systems and methods for developing an electrostatic image.

Abstract: An image forming apparatus including a latent image carrier and a developing means for charging a toner into a negative polarity by triboelectric charging, wherein the work function of the toner is set to be larger than the work function of the surface of the latent image carrier. When the apparatus includes an intermediate transfer medium, the work function of the toner is set to be larger than the work function of the surface of the intermediate transfer medium. In another embodiment, the work function ?OPC of the surface of the latent image carrier, the work function ?t of the toner, and the work function ?TM of the surface of the intermediate transfer medium are set to satisfy a relationship ?t>?OPC>?TM. These relationships help to reduce fog, and improve transfer efficiency which reduces the consumption of the toner.

Abstract: Disclosed are a developing device, a developing cartridge, a process cartridge, and an image forming apparatus in which image deficiency is prevented by absorbing the tolerance of each component and making the position of the developing roller in the thrust direction constant and which are easy to assemble. A frame member is equipped with an urging unit that axially urges the developing roller, the urging unit urging the developing roller in the direction of movement of the developing roller by the thrust force of a helical gear when a driving force is transmitted to the developing roller, to thereby make the position of the developing roller in the thrust direction constant.

Abstract: A toner separation apparatus includes a target, an inlet through which toner laden carrier enters to strike the target, an exit for carrier particles below the target, and an exit for toner particles downstream of the target. A filter can be positioned between the target and the toner exit, and a mesh to which the target is attached can be located between the inlet and the filter. The toner-laden carrier can be entrained by air driven by one or more impellers, which can be located within or without the apparatus, upstream or downstream of the target.

Abstract: A doctor blade assembly (121) for an image forming device such as a laser printer (100) includes a bracket (622) to which foam (640) is attached providing improved tolerances in the nip formed between the assembly (121) and the doctoring media. The assembly (121) includes a lip (625) which extends under the foam (640) to help secure the foam (640) and reduce the amount of adhesive required to keep the foam (640) attached. The bracket (622) is stamped from a single piece of metal providing a doctor blade assembly (121) with high stiffness that is cost effective to manufacture.

Abstract: A developer supply container detachably mountable to a developer receiving device, includes a main body for accommodating a developer; a grip member for gripping the developer supply container; an engaging member for engagement with the grip member with said grip member being elastically deformed; and a regulating portion for regulating an elastic deformation of the grip member with the engaging member being mounted on the main body.

Abstract: A developing cartridge is detachably mountable to a main assembly of an electrophotographic image forming apparatus. The cartridge includes a developing roller, for developing an electrostatic latent image formed on an electrophotographic photosensitive member, having an elastic roller portion and a shaft portion supporting the elastic roller portion, a developer regulating member; a protecting member including a contact portion provided for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member; and a supporting portion for supporting the contact portion and provided for contact with the elastic roller portion when the protecting member is demountably mounted between the developing roller and the developer regulating member. The contact portion has a hardness which is not less than a predetermined value and not more than a hardness of the elastic roller portion.

Abstract: An apparatus for developing a latent image recorded on a movable imaging surface, including: a reservoir for storing a supply of developer material including toner particles, the reservoir including a developer material mixing and transport area; a donor member being arranged to receive toner particles from the reservoir and to deliver toner particles to the image surface at locations spaced apart from each other in the direction of movement of the imaging surface thereby to develop the latent image thereon; and a climate system, associated with the reservoir, for maintaining the supply of developer material at a predefined temperature, the climate system includes a cooling element for supplying cool air to the developer material mixing and transport area, and a heating element positioned within air path for heating air to predefined temperature.

Abstract: An apparatus for digitally generating an image comprises a photoconductor assembly, a corona assembly, and a light source assembly to generate a latent image on the photoconductor. The apparatus also includes a developer assembly that includes a developer, such as powder paint, to generate an image. The apparatus may include a fuser for generating a film image. The apparatus of the present invention may include a cartridge for storing and digitally applying adhesive to the image. Furthermore, the apparatus of the present invention includes a controller for selectively controlling voltages to control thickness of the image. Additionally, apparatus may include a consumable sheet to remove excess adhesive from the substrate.

Abstract: A developing unit of an electrophotographic image forming apparatus includes at least one developing apparatus installed to be capable of accessing and being separated with respect to a photoreceptive drum and including a developing roller developing an electrostatic latent image formed on the photoreceptive drum and a gap maintenance member closely contacting the photoreceptive drum such that the developing roller accesses the photoreceptive drum in a non-contact state while maintaining a predetermined gap with the photoreceptive drum, and a guide portion formed on a frame to guide a movement of the developing apparatus. An inclined portion facing a center shaft of the photoreceptive drum is provided at a leading end of the guide portion so that the gap maintenance member closely contacts the photoreceptive drum while pressing the photoreceptive drum in a radial direction of the photoreceptive drum.

Abstract: The increasing ratio of development density to increase in potential difference between a photoreceptor and a development roller differs between the region where the potential difference is small and the region where the potential difference is large. The increasing ratio of development density at the region where the potential difference is small is smaller than the increasing ratio of development density at the region where the potential difference is large. Development is conducted under the developing characteristics in which the upper limit of the development density at the region where the increasing ratio of development density is small is at least 0.3.

Abstract: Gear (52) and resin body (2) supported on shaft (1) and between frame members (14a) and (14b) are protected from contacting a frame member. Frame (14a) has a partial hole (22) with an opening (24) and a cavity (26), which is open at the hole (22) and on the side toward the opening (24). A bearing (18) has a inner body (30) which internally is partially circular with diameter substantially the same as opening (22). The outer portion of body (30) forms an outwardly extending nub (34). Wall (36) extends across body (30). The part (38) of bearing 18 opposite body 30 has an extended part (38a) to serve as an electrical contact. A shaft end (5a) past a circular ledge (3a) is supported by bearing (18). The nub (34) fits in the cavity (26) and the wall (36) defines the proper position of rotation of the bearing. This protects gear (52) from being dislodged from its position on shaft (1).

Abstract: An image forming apparatus including an image bearing member bearing latent images; a developing unit including plural developing devices developing the latent images with developers to form visual images, each developing device including a developer bearing member bearing the developer to develop the latent image, and a developer thickness controlling member contacting the developer bearing member to control the thickness of a developer layer on the developer bearing member; and a driving device including at least one driving source, a forward rotation driving member rotated by the driving source to drive the developer bearing members to forwardly rotate to develop the latent images, and a reverse rotation driving member rotated by the driving source to drive the developer bearing members to reversely rotate when the developing operation is not performed, wherein the forward rotation driving member and the reverse rotation driving member can operate at the same time.

Abstract: An image forming apparatus includes an electrophotographic photosensitive member rotated at a peripheral speed of 150 mm/second or more and a specific toner. The toner has a weight-average particle diameter from 5 to 12 &mgr;m, and of the toner having a circle-equivalent diameter of 3 &mgr;m or more, particles with a circularity of 0.900 or more are present at a rate of 90% or more in a number-based cumulative valve. The toner also satisfies one of two sets of conditions defined by the relationship between a cut rate and a weight-average particle diameter and the relationship between a number-based cumulative valve and a weight-average particle diameter. The cut rate Z is represented by the expression: Z=(1−B/A)×100 wherein A is a concentration of all the measured particles and B is a concentration of the measured particles whose circle-equivalent diameters are 3 &mgr;m or more.

Abstract: An image forming apparatus includes a developing cartridge having a developing roller driven by developing roller drive gear, a supply roller driven by a supply roller drive gear, an input gear, a gear holder formed with a developing roller support member, supply roller support member and input gear support member, a gear holder integrally formed with the support members and a shaft receiving member formed at a location opposite the gear holder.

Abstract: There is provided a simply structured, cleanerless image forming apparatus capable of suppressing occurrence of filming without significant remodeling.