Abstract: In a developing roll, grooves of a length direction of a developing roll are formed on a surface of the developing roll on conditions that a ratio of a groove depth to a groove width is set to one or more and a ratio of a groove pitch to a groove width is set to two or more and a groove depth is set to three times or more a carrier particle size, and a magnetic pole of the inside of the developing roll is provided in a position of a doctor blade for regulating the amount of carriage of a developer roll, and further a magnetic force on the surface of the developing roll of the position of the doctor blade is set to 0.06 T or less.

Abstract: A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, the process cartridge includes an electrophotographic photosensitive drum; a developing roller for developing an electrostatic latent image formed on the photosensitive drum; a magnet disposed inn the developing roller; a drum frame supporting the photosensitive drum; a developing device frame supporting the developing roller and the magnet; an engaging member mounted to one longitudinal end of the developing device frame in engagement with one end of the developing roller and with one end of the magnet, the engaging member is provided with a projected portion at an opposite end from the end where it is in engagement with one end of the developing roller and one end of the magnet; an elastic member urging the projected portion by its elastic force so as to urge the developing roller to the photosensitive drum.

Abstract: The present invention relates to a developing apparatus which has an upstream developer bearing member for developing a latent image formed on an image bearing member and a downstream developer bearing member for developing a latent image on an image bearing member, and the downstream developer bearing member is provided downstream of the upstream developer bearing member in a moving direction of the image bearing member.

Abstract: A method of fabricating a developer bearing body includes the steps of preparing metallic base material blasting the surface of the metallic base material using spherical particles and plating the surface of the metallic base material blasted, wherein a thickness of the plating layer is two or more times as large as a particle diameter in volume average of the developer.

Abstract: A developing unit has a developer housing and a developing roll contained therein, the developer housing holding a two-component developer composed of carrier and toner. The developing roll is placed facing the opening of the developer housing and provided with a magnet member and a developing sleeve. The magnet member has multiple magnetic poles fixed thereto, and the developing sleeve is rotatably slipped on the magnet member. The developing sleeve is formed from an aluminum substrate by roughening its surface and subsequently etching the roughened surface so that the resulting etched part has an average slope angle of 15 to 20.degree..

Abstract: A developing apparatus is disclosed which has a developer container, a developer carrying member for carrying a positively chargeable developer held in the developer container and transporting the developer to a developing zone, and a developer layer-thickness regulating member for regulating the thickness of a developer layer formed on the developer carrying member. The developer carrying member has a resin coat layer formed of a resin composition containing at least a resin selected from the group consisting of a phenol resin and a polyamide resin, a conductive material and a quaternary ammonium salt compound which is positively chargeable to iron powder. The resin composition may contain a urethane resin in place of the phenol resin and polyamide resin.

Abstract: A method for manufacturing a magnetic roll for use in an electrophotographic printing machine of the type having an electrostatic latent image recorded on a photoconductive member is provided. The method includes the steps of placing a shaft in a mold cavity and molding a core in the mold cavity with the shaft in the cavity. The core defines a pocket on the periphery of the core. The method further includes the step of attaching a magnet to the pocket.

Abstract: In a developing device and a developing method in which a developer containing toners and carriers is conveyed to a developing area opposite to an image carrying member with it being held on the surface of a developer carrying member, and the toners in the developer are supplied to the electrostatic latent image formed on the image carrying member upon exerting an electric field between the developer carrying member and the image carrying member, to perform development, an impedance Zs (.OMEGA./cm.sup.2) per unit area of the surface of said developer carrying member and an impedance Zc (.OMEGA./cm.sup.2) of said carriers satisfy the condition of 1.8.times.10.sup.5 .ltoreq.Zs.multidot.Zc.ltoreq.2.1.times.10.sup.9.

Abstract: A development system is disclosed including a developer roll adapted for depositing developer material on an imaging surface having an electrostatic latent image thereon. The development system which includes a developer roll with a magnetic sleeve having a static magnetic field pattern for transporting developer material to a development zone. In operation the stationary magnetically patterned sleeve holds a thin well-defined blanket of magnetic developer on the sleeve surface. Magnetic assembly rotates and thereby generating a tangential magnetic field to move the developer blanket along the surface of sleeve; The developer blanket passes over zones on sleeve where developer material is picked up, self metering, mixing, blanket homoginization, tribo charging and developer transport occurs. The developer blanket moves to the development zone which is defined by a planar portion on the sleeve; parallel and adjacent to the imaging surface whereupon the blanket is compressed.

Abstract: A development system for developing an image with developer material including a housing containing developer material; and a magnetic roll for transporting the developer material from the housing to the image, the magnetic roll including an magnetic core and a cylindrical sleeve enclosing and rotating about the magnetic core, the sleeve having a thickness between 0.001 to 0.006 inches.

Abstract: A developer carrying member includes a substrate, the surface of which is covered with a conducting layer. The conducting layer contains a binder resin and conducting spherical particles dispersed therein having a number average particle diameter of from 0.3 .mu.m to 30 .mu.m and a true density of 3 g/cm.sup.3 or below.

Abstract: A developing sleeve for electrophotography is disclosed which has a coating film comprising electroconductive and preferably lubricating particles dispersed in an acrylic resin in which the content of components having a molecular weight lower than 500 is not higher than 3% by weight. The developing sleeve is effective in preventing development ghosts while preventing toner dusting during transfer from becoming worse and has a small environmental dependence of developing properties.

Abstract: A developing device is provided with a magnetic member having a plurality of magnetic poles N and S within a developing sleeve that rotates to transport a developer to an image bearing member. The device also includes a regulating member, which is formed of magnetic material, and which is spaced from the developing sleeve in so that the surface of the regulating member that is located on the upstream side in the developer transport direction is positioned downstream in the developer transport direction from a point of peak perpendicular magnetic flux density of the opposing magnetic pole of a magnetic member near the position at which the regulating member faces the developing sleeve, and positioned upstream in the developer transport direction from a point of 1/2 the peak perpendicular magnetic flux density of the opposing magnetic pole.

Abstract: A xerographic developer apparatus wherein the idler end of a hollow and rotatably mounted developer roller is resiliently supported for radial movement by a radially compliant hub. The hub comprises a unitary series of stainless coils that are wound about an axis of rotation of the developer roller. The series of wire coils include a first multi-turn end portion to physically engage the roller's idler end, an opposite multi-turn end portion to engage a bearing that is fixed in position to generally coincide with the roller's axis of rotation, and an intermediate multi-turn portion that is free of physical engagement with either of the roller's idler end or the bearing. The intermediate multi-turn portion resiliently support the roller's idler end for needed radial movement relative to the bearing.

Abstract: A magnet system for an image-forming apparatus comprising an image-forming element which is capable of electrically and/or magnetically attracting a toner powder and is movable relative to the magnet system. The magnet system includes a support at least one ferromagnetic body and a clamping device. The support is surrounded by a rotatable sleeve and arranged such that the circumferential surface of the sleeve faces the surface of the image-forming element in a linear image-forming zone extending normal to the direction of movement of the image forming element. The at least one ferromagnetic body has magnets fixed in the support and defines a localized magnetic field in the image-forming zone. The clamping device will engage the ferromagnetic body to secure the body in the support in a non-positive manner, thereby allowing differential thermal expansion of the magnets and the support.

Abstract: A thin film of electroless plated nonmagnetic nickel/phosphor (Ni/P) forms at least the external cylindrical surface of a hollow magnetic brush roller. The plated nonmagnetic film or layer is deposited at least one the exterior cylindrical surface of a hollow, electrically conductive, metal, nonmagnetic, aluminum roller or nonmagnetic stainless steel roller. Alternatively, the plated film is deposited on both the external and internal surfaces of such a development roller that is formed of an electrically conductive and nonmagnetic plastic material. The plated film is electrically conductive and relatively transparent to the magnetic fields that are generated by stationary permanent magnets that are positioned inside of the hollow and rotatable magnetic brush roller. The roller is intended for use in xerographic copiers, printers, and the like. The invention is usable both in the new-build of magnetic brush developers and in the refurbishing/recycling of existing magnetic brush developers apparatus.

Abstract: A developer is carried on a developer-carrying member and conveyed to a developing region to be used for developing an electrostatic latent image formed on an electrostatic latent image-bearing member. The developer includes a non-magnetic toner, and the toner includes toner particles containing 5-30 wt. % of a low-softening compound and having a shape factor SF-1 of 100-130. The developer-carrying member has a developer-carrying surface satisfying the conditions of:0.2 .mu.m.ltoreq.Ra.ltoreq.5.0 .mu.m,10 .mu.m.ltoreq.Sm.ltoreq.80 .mu.m,and0.05 .ltoreq.Ra/Sm.ltoreq.0.5,wherein Ra denotes a center line-average roughness, and Sm denotes an average spacing between unevennesses. The toner shows good fixability and fluidity and is yet uniformly applied and conveyed to be used for developing because of the appropriate surface roughness of the developer-carrying member. The developed toner image can be transferred at a high transfer ratio.

Abstract: A developing roller includes a magnet roller and a rotatable sleeve thereon. The sleeve is covered with a surface coating of a metal, alloy, metal nitride, metal oxide, metal carbide or metal sulfide by dry plating. The coating has a resistivity of up to 0.01 .OMEGA.cm. The sleeve is fully wear resistant at its surface. Formation of the coating by dry plating minimizes the variation of coating thickness to improve the dimensional precision of the sleeve surface. The developing roller and a developing apparatus equipped therewith can produce images of quality for a long time.

Abstract: A magnetic brush development roller assembly for an electrographic printer, includes a cylindrical multipole magnet mounted for rotation about a cylindrical axis within a cylindrical shell. The stationary shell surrounding the multipole magnet defines an axial slot for receiving an imaging head, and has an increased thickness in the neighborhood of the slot and a reduced thickness in a neighborhood diametrically opposite the slot, whereby eddy currents generated by rotation of the magnet within the shell and hence drag on the magnet are reduced.

Abstract: A developer roll for use in electrophotographic copying machines and printers. The roll has a coating which is electrically conductive. Also disclosed are the materials comprising the roll and its coating, and a process for formulating the materials and for applying them to the surface of the roll by powder-coating.

Abstract: A developer roll for use in an electrophotographic printing machine of the type having an electrostatic latent image recorded on a photoconductive member in which a voltage differential is applied between the roll and a region adjacent the roll is provided. The developer roll includes a wound roll of media and a layer of resin. The wound roll is formed from a sheet of the media. The layer of resin is applied to the periphery of the wound roll. The layer of resin and the roll of media are selected of materials to obtain a decay rate relating to the electrical response of the layer of resin to the applied voltage differential.

Abstract: A developing unit including a housing having an opening defining a developing zone, an applicator for applying particulate developer through the opening towards an electrostatographic image to be developed, and a paddle wheel for agitating developer within the housing, for scooping up developer from within the housing and projecting scooped-up developer towards the applicator. A hopper, located outside the width of the development zone supplies toner to the housing, and a primary spiral screw conveys developer from the hopper across the width of the development zone in one direction, while a secondary spiral screw receives developer from the primary spiral screw and conveys developer across the width of the development zone in an opposite direction. A passageway outside the width of the development zone enables the return of developer from the secondary spiral screw to the primary spiral screw.

Abstract: A method for treating a magnet roll including the steps of providing a permanent magnet member having an outer circumferential surface and a plurality of axially extending magnetic poles formed in the outer circumferential surface, slidably surrounding the member with a non-magnetic metal sleeve of hollow cylindrical shape, the sleeve and the member being rotatable relative to each other, blasting a surface of the sleeve with spherical particles of a non-magnetic material having a density in a range of from 3 to 4 g/cm.sup.3 and Mohs' hardness in a range of from 11 to 14 to produce a surface roughness (R.sub.z) in a range of from 0.5 to 8 .mu.m.

Abstract: An image forming unit includes structure to prevent leakage of initial developer containing magnetic carrier and magnetic toner from a case. The image forming unit includes a photoconductive drum, a developing sleeve, and a trimming blade. Auxiliary sealing members are attached to the opposite ends of the trimming blade to stop up gaps between side sealing members in sliding contact with the opposite ends of the developing sleeve, and a protective sheet is removably inserted in the gap between the developing sleeve and the trimming blade. Ferromagnetic strips capable of being magnetized by the magnet roller are attached to the reverse side of the protective sheet at the opposite sides of one end of the protective sheet. The ferromagnetic strips magnetically attract the developer that is about to leak through the gaps to completely prevent leakage of the developer.

Abstract: A developing apparatus in which a stationary multipole permanent magnet is placed in a sleeve and in which development is performed by bringing a developer, which contains at least carrier and toner particles and is held on the periphery of a sleeve by use of the magnetic force of the multipole permanent magnet, into contact with a photo-conductive body owing to the rotation of the sleeve. For securing image density and for preventing the deposition of carrier onto the photo-conductive body, two magnetic pieces, each of which is arranged lengthwise in the direction of the axis thereof and which have the same polarity, are placed in a region in the multipole permanent magnet which faces the photo-conductive body in such a manner as to adjoin in the circumferential direction of said permanent magnet. This results in generation of the distribution of a magnetic field which has two peaks of magnetic force.

Abstract: A developing apparatus including a fixed permanent magnet member 4 having a plurality of magnetic poles on the surface and a non-magnetic cylindrical sleeve 5 which is rotated around the permanent magnet member 4 at a position opposing a movable image-bearing member 1 having an electrostatic latent image on the surface, to form a developing region Z; causing a developer 3 to be magnetically attracted onto a surface of the non-magnetic cylindrical sleeve 4, and rotating the non-magnetic cylindrical sleeve 4 to convey the developer 3 into the developing region Z, and developing the electrostatic latent image with the magnetic toner 3, the moving velocity of the developer 3 in the developing region Z being higher than the peripheral velocity of the non-magnetic cylindrical sleeve 5.