Abstract: A toner for developing a latent electrostatic image to a toner image, including a binder resin, and a magnetic material which is blackened by coating the surface of a magnetic powder with a coloring agent, the magnetic material being in an amount of 10 wt.% to 40 wt.% of the entire weight of the toner, a method of forming an image, using a two-component developer containing the toner, an image formation apparatus using the two-component developer, and a toner container containing therein the toner, and an image formation apparatus equipped with the toner container are proposed.

Abstract: A developing unit includes a developer containing unit that contains developer, a developer carrier that has a moving surface, and carries the developer, a magnetic force generator that attracts the developer onto the moving surface by a magnetic force generated from a plurality of magnets, and a restricting member that restricts a layer thickness of the developer. The magnets includes a restricting magnet arranged closest to the restricting member and has a restricting magnetic pole of which a first surface toward the moving surface and a second surface toward an upstream adjacent magnet that is arranged so as to be adjacent to an upstream side of the developer carrier in a direction of movement of the moving surface and has an upstream adjacent magnetic pole form a ridged corner portion, and the ridged corner portion is chamfered.

Abstract: A developer layer thickness regulating device for a developing unit improves the sealing effect of a developer by regulating a thickness of a developer layer formed on a developing roller. The device includes a blade having a blade body that is in resilient contact with the developing roller. A bent part is formed on the blade body and extends at a predetermined angle from a developing roller contact part that is in contact with the developing roller, and a recessed part formed on the bent part. A sealing member is in contact with the blade. The sealing member overlaps with the recessed part.

Abstract: A developing apparatus which uses a two-component developer consisting of a toner and carrier. The ratio between the amount of the developer M1 which is drawn onto a developing sleeve and refluxes while being regulated by a doctor blade, and the amount of the developer (drawn amount) M2 which passes through the doctor blade is M1/M2<10. The toner is a negatively-charged toner. In a charge amount distribution the number of toners of ?1 fc/10 ?m or more is 20% or less of the total number of toners.

Abstract: A regulating device and method regulating the thickness of a toner of an image forming apparatus. The device and method include a blade body for elastically contacting a developing roller supplying toner to a photosensitive medium, and a bending portion bent at a predetermined angle from the contacting portion of the blade body and the developing roller to regulate the layer thickness of the toner that is transferred to the developing roller, wherein the blade portion is formed such that its height is gradually reduced toward both ends of the bending portion so that the toner supplied to the developing roller goes over the ends of the bending portion, and a developing unit employing the same.

Abstract: A development unit including: (a) a developer storage storing a developer; (b) a developer receiver disposed in an end portion of the developer storage and having a depository surface on which the developer is to be deposited; and (c) a regulator including a contact portion held in pressing contact with the depository surface of the developer receiver so as to regulate a thickness of the developer deposited on the surface of the developer receiver The regulator farther includes a base portion contiguous to the contact portion and extending from the contact portion in a direction toward the other end portion of the developer storage. An acute angle is defined by a base-portion plane on which the base portion of the regulator lies and a tangential plane which is tangent, at a contact portion of the depository surface held in contact with the contact portion of the regulator, to the depository surface.

Abstract: A developing device includes a developer carrier and a developer regulating member including a developer regulating part opposing a surface of the developer carrier to regulate the developer carried and conveyed by the developer carrier. The developer regulating member is formed from a single metallic member and includes a space that faces an inner surface of the metallic member. The space extends in a direction perpendicular to a moving direction of the surface of the developer carrier. The developing device can include a cooling device that cools the developer regulating member from an inner surface side of the metallic member facing the space.

Abstract: A toner layer regulating system for an electrophotographic image forming apparatus includes a toner carrier; a toner regulating member (e.g., doctor blade) disposed proximate the toner carrier, with the toner regulating member having a first surface disposed toward the toner carrier and forming a nip with the toner carrier. The toner regulating member comprise a flexible metallic substrate and a metallic coating on the first surface in an area thereof forming the nip. The coating on the toner regulating member comprises a material selected from the group consisting of molybdenum, tungsten carbide, and alloys thereof. The coating may be substantially homogeneous and/or have a thickness of not more than 30 um. The coating may have a relatively smooth surface roughness of ?2.0 um Ra.

Abstract: A two-component developing apparatus includes a developer carrier, a first regulating member, a developer container, and a toner container. The developer carrier is configured to carry and transfer the two-component developer including a magnetic carrier. The first regulating member is configured to regulate an amount of the two-component developer carried and transferred by the developer carrier. The developer container is configured to receive the developer removed by the first, regulating member. The toner container is configured to supply toner to the developer carrier. The developer stirring member is configured to carry and stir the developer between the first regulating member and the second regulating member. The second regulating member includes a support member on one end side of the second regulating member in its longitudinal direction to which greater amount of the developer is supplied than to another end side of the second regulating member.

Abstract: An electrophotographic image forming apparatus of the present invention frees images from various defects including the thinning of horizontal lines, the omission of the trailing edge of an image, background contamination, granularity particular to a halftone image, carrier scattering, and image noise. Further, the apparatus of the present invention solves problems ascribable to patches used to sense image density. Moreover, the apparatus of the present invention faithfully reproduces tonality and has a high developing ability.

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: A developing blade member for regulating a thickness of a layer of a developer on a peripheral surface of a rotatable developing roller enclosing a magnet roller, wherein a scraper for scraping the developer toward longitudinally inside of the developing roller is provided at a longitudinal end of the developing roller, the developing blade member including an elastic member for regulating the thickness of the layer of the developer on the peripheral surface of the developing roller; a metal plate for supporting the elastic member; a projection projecting toward the developing roller, the projection being provided at each of longitudinal ends of the metal plate, wherein an inside end of the projection, with respect to the longitudinal direction of the developing roller, is disposed inside of an inside end of the scraper and in a non-image-formation region.

Abstract: A metering blade suspension system utilizes a leaf spring that performs multiple combined functions such as supporting a metering blade assembly, controlling the angle, position and/or load of the blade assembly while allowing the assembly to pivot in a quasi-frictionless motion, locking the blade assembly in place, providing an electrical connection and/or bleeding static charge.

Abstract: In an image forming apparatus where toner is supplied to a photosensitive member via a toner supply roller and a developing roller, the toner being charged by the friction contact between toner supply roller and the developing roller, a regulating blade is in contact with the developing roller at a point between contact between the toner supply roller and the developing roller and between the developing roller and the photosensitive member. The area between the contact between the toner supply roller and the developing roller and where the layer regulating blade contacts the developing roller constitutes a first region and the area between the contact between the regulating blade and the developing roller and the developing roller and the photosensitive member constitutes a second region. The charge amount per unit area in the two regions is substantially equal.

Abstract: A developing method of the present invention is practicable with a developing unit of the type including a rotatable, nonmagnetic sleeve and a rigid metering member. A two ingredient type developer made up of magnetic carrier grains and toner grains is magnetically deposited on the sleeve. The metering member meters the amount of the developer deposited on the sleeve. The sleeve has surface roughness Rz ranging from 5 ?m to 20 ?m. The carrier grains each are covered with a coating layer containing at least binder resin and grains. The ratio of the diameter D of the individual grain contained in the coating layer to the thickness h of the binder resin layer lies in the range of 1<D/h<10. The carrier grains have a weight-mean grain size ranging from 20 ?m to 60 ?m.

Abstract: The development apparatus develops a latent image formed on a photo-conductor using a developer composed of a toner and a magnetic currier particle. A development sleeve carries the developer on an outer surface thereof so as to transfer the developer to the photo-conductor. A developer application mechanism applies the developer to the outer surface of the development sleeve. A plurality of magnets are provided inside the development sleeve so as to generate a magnetic field so that a magnetic brush is formed by the developer. The magnetic brush is brought into contact with said latent image carrier in a development area where the developer carrier is contiguous to the latent image carrier and the magnetic field between the latent image carrier and the developer separates the toner from the magnetic carrier of the magnetic brush. The wherein the magnetic brush is separated from the latent image carrier outside the development area.

Abstract: A developing device includes a developer carrier that carries a developer and a developer restricting member that restricts a layer thickness of the developer on the developer carrier. The developer carrier carries the developer in such a manner that a thickness Tup of a layer of the developer when the layer passes through the developer restricting member and a gap Gd between the developer restricting member and the developer carrier satisfy an inequality 7<Tup/Gd<20.

Abstract: A developing unit includes a developer containing unit that contains developer, a developer carrier that has a moving surface, and carries the developer, a magnetic force generator that attracts the developer onto the moving surface by a magnetic force generated from a plurality of magnets, and a restricting member that restricts a layer thickness of the developer. The magnets includes a restricting magnet arranged closest to the restricting member and has a restricting magnetic pole of which a first surface toward the moving surface and a second surface toward an upstream adjacent magnet that is arranged so as to be adjacent to an upstream side of the developer carrier in a direction of movement of the moving surface and has an upstream adjacent magnetic pole form a ridged corner portion, and the ridged corner portion is chamfered.

Abstract: A developer unit of an electrophotographic image forming apparatus includes a blocking blade having a magnetic fluid and a magnet. The magnetic fluid contacts a developer roller and the metering blade to prevent a developer from flowing to both ends of the metering blade. The magnetic fluid is fixed to the magnet which applies a pressure to the magnetic fluid so that the magnetic fluid contacts the developer roller and the metering blade. Since the magnetic fluid contacts the developer, wear of elements of the developer unit can be reduced, thereby securing durability of the developer unit. Also, a wrap-around phenomenon of the developer can be prevented.

Abstract: A non-magnetic mono-component developing device of the present invention can create a toner layer having a uniform thickness with uniform static charge characteristics across the full range of the image forming area on the peripheral surface of the developing roller, so as to form images of good quality, and includes a doctor blade which has a distal end as a free end, extended to the upstream side with respect to the direction of rotation of the developing roller and can regulate the thickness of the toner layer by abutting part of the side flat surface of the distal end portion against the peripheral surface of the developing roller, and is characterized in that the doctor blade has, at its distal end, an extension projected in the tangent direction from the abutment S and a bent portion (bent angle &thgr;) angled so as to be positioned away from the peripheral surface, and Z is specified so as to satisfy the following relation: 0<Z≦[(Rr+4×&phgr;t)2−Rr2]1/2, where Z repres

Abstract: In an image forming apparatus including a developing device, an inequality of 1≦(&agr;/100)×Vr×Hr1/3<3.5 is satisfied, wherein Vr denotes the peripheral speed ratio of an outer circumferential surface of a developer carrying member to the outer circumferential surface of an image carrying member, Hd denotes a spacing of the outer circumferential surface of the developer carrying member to the outer circumferential surface of the image carrying member, Hh denotes an average value of a height of a magnetic brush layer, Hr denotes a ratio of an average value of the height Hh to the spacing Hd, and &agr; (%) denotes a coverage ratio of an area of the magnetic brush layer to cover the outer circumferential surface of the developer carrying member to the outer circumferential surface of the developer carrying member.

Abstract: A developing method of the present invention develops a latent image formed on an image carrier with a developing device including at least a developer carrier and a doctor blade. The developer carrier magnetically causes a two-ingredient type developer made up of toner grains and magnetic carrier grains to deposit thereon and conveys it to a developing zone where the developer carrier faces the image carrier. The doctor blade regulates the thickness of the developer forming a layer on the developer carrier. The ratio of a dynamic torque W (kgf·cm) to act on the developer while the developing device is in operation to an amount of toner grains M (g) contained in the developer is selected to be 4.0×10−2 or below.

Abstract: A developing device of the present invention includes stationary layer angle setting means. Assume that a developer layer, staying at a position upstream of a metering member in a direction in which a developer carrier conveys a developer, consists of a stationary layer in which the developer is not replaced and a flowing layer in which it is replaced, that an angle between, as seen from the axis of the developer carrier, the upstream edge portion, in the above direction, of the end portion of the metering member, which faces the developer carrier, and a position where the end of the stationary layer upstream of, but remote from the edge portion, is located is &thgr;d, and that an angle between, as seen from the above axis, the edge portion and a position where a magnetic pole is positioned just upstream of a doctor pole in the above direction is &thgr;1. Then, the angle &thgr;d lies in a preselected range relative to the angle &thgr;1.

Abstract: A two-component developing apparatus includes a developer carrier, a first regulating member, a developer container, and a toner container. The developer carrier is configured to carry and transfer the two-component developer including a magnetic carrier. The first regulating member is configured to regulate an amount of the two-component developer carried and transferred by the developer carrier. The developer container is configured to receive the developer removed by the first, regulating member. The toner container is configured to supply toner to the developer carrier. The developer stirring member is configured to carry and stir the developer between the first regulating member and the second regulating member. The second regulating member includes a support member on one end side of the second regulating member in its longitudinal direction to which greater amount of the developer is supplied than to another end side of the second regulating member.

Abstract: An image formation apparatus develops an electrostatic latent image with a two-component developer consisting of magnetic carriers and toners by using a development apparatus and a latent image supporter including a filler in an outermost layer thereof, the development apparatus having a developer supporter, which has an internally fixed magnetic body and rotates while supporting a developer on a surface thereof, and a developer quantity controller controlling a quantity of the developer which is supported by the developer supporter facing the magnetic body and controlling a height of magnetic brushes and consisting of materials having rigidity or rigidity and magnetic properties, wherein a ratio (Gp/Gd) of a development gap to a doctor gap between the developer supporter and the controller is from 0.7 to 1.0, and a weight-averaged particle diameter of a developer carrier is from 20 to 60 &mgr;m.

Abstract: An electrophotographic image forming apparatus of the present invention frees images from various defects including the thinning of horizontal lines, the omission of the trailing edge of an image, background contamination, granularity particular to a halftone image, carrier scattering, and image noise. Further, the apparatus of the present invention solves problems ascribable to patches used to sense image density. Moreover, the apparatus of the present invention faithfully reproduces tonality and has a high developing ability.

Abstract: A development apparatus includes a development roller, a supplying roller, and a toner layer regulating member. The development roller contacts an image carrying member and develops an electrostatic latent image into a toner image on the image carrying member. The development roller may be made of aluminum and is rotatably mounted in the apparatus. The supplying roller supplies toner to the development roller. The toner layer regulating member regulates the toner to form a thin film on the development roller. The toner layer regulating member has a roller shape, a surface roughness Rz in a range of from 0.5 &mgr;m to 2 &mgr;m, and a dynamic friction coefficient in a range of from 0.1 to 0.8.

Abstract: The invention relates generally to processes for electrostatic image development, and setpoints that provide uniform image development. In particular, an apparatus and process having a magnetic brush that implements a rotating magnetic core within a shell is disclosed. The process implements one or more of the following optimum setpoints: a range of shell surface speeds that provide uniform toning density, a range of shell surface speeds that prevent toner plate-out, a skive spacing that minimizes sensitivity to variation, a magnetic core speed that minimizes sensitivity to variation, and an imaging member spacing that minimizes sensitivity to variation.

Abstract: A developing device, used in an image forming device where a developer supported on a developer supporter is thinned by a thinning member, and after being thinned, the developer is adhered to develop a latent image on an image supporter. An adjacent member (a developer scattering blocking member) is disposed at a position adjacent to the thinning member's downstream side in the developer supporter's moving direction, and the adjacent member's thinning member side of the opposite surface that is opposite to the developer supporter and the tip of the thinning member are disposed with an equal distance from the developer supporter. The opposite surface is gradually separated from the developer supporter at the downstream side of the developer supporter's moving direction.

Abstract: A developing device for feeding a developer stored therein to an image carrier of the present invention includes a sleeve facing the image carrier for causing the developer deposited thereon to contact a latent image formed on the image carrier. A regulating member faces the sleeve for regulating the thickness of the developer that forms a layer on the sleeve. A guide member has a guide surface for guiding the developer regulated by the regulating member toward the surface of the image carrier. The guide surface has a conductive surface facing the sleeve. The developing device protects the image carrier from defective images ascribable to impurities, which include deteriorated toner and paper dust, without resorting to a filter mechanism or a bias for collection.

Abstract: A developing blade member for regulating a thickness of a layer of a developer on a peripheral surface of a rotatable developing roller enclosing a magnet roller, wherein a scraper for scraping the developer toward longitudinally inside of the developing roller is provided at a longitudinal end of the developing roller. the developing blade member including an elastic member for regulating the thickness of the layer of the developer on the peripheral surface of the developing roller; a metal plate for supporting the elastic member; a projection projecting toward the developing roller, the projection being provided at each of longitudinal ends of the metal plate. wherein an inside end of the projection. with respect to the longitudinal direction of the developing roller, is disposed inside of an inside end of the scraper and in a non-image-formation region.

Abstract: An image formation apparatus develops an electrostatic latent image with a two-component developer consisting of magnetic carriers and toners by using a development apparatus and a latent image supporter including a filler in an outermost layer thereof, the development apparatus having a developer supporter, which has an internally fixed magnetic body and rotates while supporting a developer on a surface thereof, and a developer quantity controller controlling a quantity of the developer which is supported by the developer supporter facing the magnetic body and controlling a height of magnetic brushes and consisting of materials having rigidity or rigidity and magnetic properties, wherein a ratio (Gp/Gd) of a development gap to a doctor gap between the developer supporter and the controller is from 0.7 to 1.0, and a weight-averaged particle diameter of a developer carrier is from 20 to 60 &mgr;m.

Abstract: An image forming apparatus is provided for obtaining excellent developing properties using toner with small particle diameters and for forming high-quality visual images. In a developing device of an image forming apparatus, a two-component developer is used which satisfies conditions that volume mean particle diameter dt of a toner is 3˜5 &mgr;m (Condition 1), volume mean particle diameter dc of a carrier is 5 dt˜10 dt (Condition 2), and a weight ratio Rw of the toner and the carrier is 1.6 (dt/dc) ×(&rgr;t/&rgr;c)˜2.4 (dt/dc)×(&rgr;t/&rgr;c) (Condition 3, where &rgr;t and &rgr;c are density of the toner and the carrier, respectively). A main magnetic pole M of a rotary sleeve is arranged in the vicinity of the closest position of the rotary sleeve and an image forming body, and the closest distance D between the rotary sleeve and the image forming body satisfies a condition that D is 0.5 H˜0.8 H for the free tip height H of a magnetic brush B of the main magnetic pole M.

Abstract: In a developing device according to the present invention, a developing roller 8 has a fixed shaft 12 and a sleeve 13. The length of a draw-up magnetic pole N3 provided in the fixed shaft 12 is made shorter than the length of a main magnetic pole N1. Accordingly, the amount of a developer adhering to both ends of an outer peripheral surface of the sleeve 13 is reduced, so that the density of the developer at both the ends of the sleeve 13 is maintained in suitable conditions in a state where the developer is over the main magnetic pole N1.

Abstract: An image forming apparatus of the present invention includes a developing device including a rotatable, nonmagnetic developer carrier and a magnetic field forming device. In a developing region where the developer carrier faces an image carrier, the magnetic field forming device causes a developer made up of toner and magnetic grains to rise on the developer carrier in the form of a magnet brush. In the developing region, the magnet brush on the developer carrier is caused to move at a higher speed than the surface of the image carrier in the same direction as and in contact with the surface of the image carrier, thereby developing the latent image. The toner of the developer is magnetic toner. Flux density set up in the developing region outside of the surface of the developer carrier in a normal direction has an attenuation ratio of 50% or above.

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 im

Abstract: In a development system there is provided a developer transport adapted for depositing developer material on an imaging surface having an electrostatic latent image thereon, including: a housing defining a chamber storing a supply of developer material including carrier and toner; a donor member, mounted partially in the chamber and spaced from the imaging surface, for transporting developer on an outer surface thereof to a region opposed from the imaging surface, the donor member having a magnetic assembly having a plurality of poles, a sleeve, enclosing the magnetic assembly, rotating about the magnetic assembly; a plurality of trim bars positioned about the donor member at a predefined positions and spacing around the donor member, the plurality of trim bars progressively reducing developer bed height of the developer material on the donor member to a predefined developer bed height within a development nip.

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 includes rotatable first and second developer carrying members carrying developer thereon to develop an electrostatic image formed on an image bearing member. The first and second developer carrying members are provided with a plurality of nonrotary magnetic poles therein, respectively a developer regulating member regulates the amount of the developer carried on the second developer carrying member.

Abstract: A toner suitable for use in electrophotography, etc., is composed of toner particles each containing a binder resin, a colorant and a wax component. The toner has a number-average particle size of 2-6 &mgr;m and a standard deviation in particle size of below 2.6 based on a number-basis distribution of circle-equivalent diameters, an average circularity of 0.970-0.995 and a standard deviation in circularity of below 0.030 based on a circularity frequency distribution, and a residual monomer content of at most 500 ppm. The toner particles have such a microtexture as to provide a particle cross section as observed through a transmission electron microscope (TEM) exhibiting a matrix of the binder resin and a particle of the wax dispersed in a discrete form in the matrix of the binder resin.

Abstract: A position where a transport amount regulation member is opposed to a developing roller is in an area wherein the magnetic flux density in the tangent line direction becomes 95% or less of the maximum value upstream in the developer transport direction from the position at which the magnetic flux density in the normal direction formed by two magnetic poles on both sides of the transfer amount regulation member on the sleeve roller surface of the developing roller becomes 0 gausses and is in an area wherein the magnetic flux density in the normal direction becomes 90% or less of the maximum value of the upstream pole in the developer transport direction.

Abstract: In an image forming apparatus including a developing device, an inequality of 1≦(&agr;/100)×Vr×Hr1/3<3.5 is satisfied, wherein Vr denotes the peripheral speed ratio of an outer circumferential surface of a developer carrying member to the outer circumferential surface of an image carrying member, Hd denotes a spacing of the outer circumferential surface of the developer carrying member to the outer circumferential surface of the image carrying member, Hh denotes an average value of a height of a magnetic brush layer, Hr denotes a ratio of an average value of the height Hh to the spacing Hd, and &agr; (%) denotes a coverage ratio of an area of the magnetic brush layer to cover the outer circumferential surface of the developer carrying member to the outer circumferential surface of the developer carrying member.

Abstract: A developing method of the present invention is practicable with a developing unit of the type including a rotatable, nonmagnetic sleeve and a rigid metering member. A two ingredient type developer made up of magnetic carrier grains and toner grains is magnetically deposited on the sleeve. The metering member meters the amount of the developer deposited on the sleeve. The sleeve has surface roughness Rz ranging from 5 &mgr;m to 20 &mgr;m. The carrier grains each are covered with a coating layer containing at least binder resin and grains. The ratio of the diameter D of the individual grain contained in the coating layer to the thickness h of the binder resin layer lies in the range of 1<D/h<10. The carrier grains have a weight-mean grain size ranging from 20 &mgr;m to 60 &mgr;m.

Abstract: The doctor blade consists of at least a substrate provided with an element having a face adapted for working with a magnetic roller, the element being made at least partly of an elastic material, wherein the face adapted for working with a magnetic roller has an abrasion resistance of less than 0.5 g (measured according to the method ASTM D4060).

Abstract: A developing device of the present invention uses a developer containing magnetic toner grains and includes a main pole for development disposed in a sleeve. Flux density generated by the magnetic pole in a direction normal to the surface of the sleeve outside of the surface has an attenuation ratio of 50% or above. The toner grains have a weight mean grain size of 6.0 &mgr;m to 8.0 &mgr;m while the toner grains having grain sizes of 5 &mgr;m and below occupy 40 number % to 80 number % of the entire developer. The toner grains have magnetization strength of 10 emu/g to 25 emu/g in a magnetic field of 5 kOe or magnetization strength of 7 emu/g to 20 emu/g in a magnetic field of 1 kOe. The toner grains reduce toner scattering and image defects despite that they are magnetic, thereby implementing ultrahigh resolution, image reproducibility.

Abstract: In a development system there is provided a developer transport adapted for depositing developer material on an imaging surface having an electrostatic latent image thereon, including: a housing defining a chamber storing a supply of developer material including carrier and toner; a donor member, mounted partially in the chamber and spaced from the imaging surface, for transporting developer on an outer surface thereof to a region opposed from the imaging surface, the donor member having a magnetic assembly having a plurality of poles, a sleeve, enclosing the magnetic assembly, rotating about the magnetic assembly; a plurality of trim bars positioned about the donor roll at a predefined positions and spacing around the donor roll, the a plurality of trim bars progressively reducing developer bed height of the developer material on the donor member to a predefine developer bed height within the development nip.

Abstract: The invention relates generally to apparatus for electrostatic image development and, in particular, apparatus that implement a magnetic brush with a drum photoconductor. According to an aspect of the invention, a method and apparatus for developing an electrostatic image are provided implementing a drum photoconductor and a magnetic brush contacting the drum photoconductor. The magnetic brush includes a mixture of toner and hard magnetic carriers.

Abstract: A composite doctor blade comprises a steel support band configured with a width and thickness suitable for mounting in a blade holder, with tensile and yield strengths suitable for a selected doctoring application. A wear resistant strip of high speed steel is integrally joined to an edge of the support band. The wear resistant strip has tensile and yield strengths higher than those of the support band, and has a hardness of between about 55 to 75 Rc.

Abstract: A two-component developer unit of an electrophotographic image forming apparatus includes a developer rectifier having a lifting guide portion and a developer collection guide portion. The lifting guide portion guides a developer agitated by an agitating unit upward along a circumferential direction of a developer magnet roller. The developer collection guide portion keeps the developer to move down to the lifting guide portion between a developer blade and the lifting guide portion. A non-uniformity of image intensity can be solved without giving an overweight load to the developer and a photoreceptor and without increasing a driving torque of the developer and the photoreceptor.

Abstract: A developing device for an image forming apparatus of the present invention includes a developing roller made up of a sleeve and a magnet roller and a doctor facing the surface of the sleeve. The edge of the doctor faces the sleeve at a particular position selected to stabilize the amount of a developer to be scooped up, protect the developer from deterioration, and allow an adequate amount of charge to deposit on the developer by friction.