Abstract: A development device includes a developer support body including a non-magnetic hollow body which contains a magnetic field generator and attracts a developer onto an outer surface by a magnetic force of the magnetic field generator, a magnetic member being disposed around the magnetic field generator and exerting a magnetic force on the magnetic field generator, and an anti-deflection magnetic field generator being provided around the hollow body and exerting a magnetic force on the magnetic field generator to prevent a deflection of the magnetic field generator by negating at least one of the magnetic force of the magnetic member and a gravitational force due to empty weight of the magnetic field generator.

Abstract: A magnet roller includes a cylindrical roller body including a side surface in which a groove is formed, a magnet body which is disposed in the groove, and a magnetic metal member which is attached to a surface of the magnet body, which is remote from an opening of the groove.

Abstract: A magnetic particle carrying device includes a magnetic field generator and a hollow cylindrical structure. The magnetic field generator generates a magnetic field. The hollow cylindrical structure encases the magnetic field generator and attracts magnetic particles on an external surface of the hollow structure using the magnetic field. The external surface of the hollow cylindrical structure is provided with a plurality of elliptical depressions. The depressions include first type depressions and second type depressions. A long axis of a first type of elliptical depression is substantially extending in an axial direction of the hollow cylindrical structure, and a long axis of a second type of elliptical depression is substantially extending in a circumferential direction of the hollow cylindrical structure. The external surface of the hollow cylindrical structure has more elliptical depressions of the second type than elliptical depressions of the first type.

Abstract: The long magnet includes a magnet block made of a mixture of rare earth magnetic powder, thermoplastic resin particles, fluidity additive, pigment, wax and charge control agent, and a reinforcing member to reinforce the magnet block. At least part of the reinforcing member is arranged inside of the magnet block.

Abstract: A development magnet roller for use in a development roller of an electrophotographic image forming apparatus is provided. The development magnet roller has a development pole to form a magnetic field causing a developer born on a surface of the development roller including the development magnet roller to rise in a form of a series of ears in a development area of the image forming apparatus where the development roller opposes an image bearing member, and in a magnetic flux density distribution in a normal line direction of the development pole, a peak magnetic flux density is 120 mT or greater, a zero gauss region width is 70° or greater, and a half-value region width is 40° or smaller.

Abstract: A developer holding member includes a magnetic field generating device and a hollow body including the magnetic field generating device thereinside, and attracting a developer to an external surface thereof with magnetic force of the magnetic field generating device. The external surface of the hollow body is randomly provided with a large number of depressions, and a peak intensity of a spectrum within a range of wavelengths not more than 1 mm, which is figured out by performing a frequency analysis using a profile curve in a circumferential direction of the external surface, is not more than 12.

Abstract: A development device including a developer carrier including a cylindrical magnetic field-generation member having a surface portion provided with a plurality of magnetic poles and a rotatable hollow member which is disposed inside the magnetic field-generation member and formed of a non-magnetic material, a developer control member configured to control an amount of a developer which is carried on the developer carrier and fed to an image supporter disposed to office the developer carrier, and an agitator provided upstream the developer control member in a rotating direction of the developer carrier and configured to feed the developer contained in a developer-containing tank in an axial direction of the hollow member, a developer conveying pole being provided on the surface portion of the magnetic field-generation member to form a developer separation area for separating the developed developer which has thin toner density from the hollow member into the developer-containing tank on the surface portion of t

Abstract: A developing roller includes a developing sleeve having a nonmagnetic material, and a magnet roll provided inside the developing sleeve and formed by dispersing a magnetic powder in a polymer compound. A portion of the magnet roll corresponding to a developing pole of the magnet roll is equipped with a main-pole molded magnet whose magnetic force per unit of volume is greater than that of the magnet roll. A magnetic pole adjacent to the developing pole of the magnet roll downstream in the developer conveyance direction has a peak magnetic flux density on the developing sleeve greater than that of the developing pole, and has a half value width, which is the width of the magnetic pole at which a magnetic flux density of one-half the peak magnetic flux density is exhibited, greater than that of the developing pole.

Abstract: A development roller, including a development sleeve disposed near a photo conductive drum, a magnetic roller disposed in the development sleeve, and a supplying device configured to supply a developer including a toner and a magnetic carrier to the photo conducive drum uniformly, the development sleeve having an outer surface on which the developer including the toner and the magnetic carrier is adsorbed by a magnetic force of the magnetic roller.

Abstract: In a developing device for an image forming apparatus of the present invention, use is made of a magnetic molding produced by compression-molding a magnet compound material in a magnetic field. The magnet compound material contains, in addition to magnetic powder and fine, thermoplastic resin grains that are major components, at least one of a pigment and a charge control agent.

Abstract: A magnet compound material to be compression molded, said magnet compound material comprising a magnetic powder and a binder resin particles, wherein a ratio of Dv to Dn is in a range of 1.1 to 1.3, Dv and Dn of the binder resin particles denote the volume average particle diameter and the number average particle diameter, respectively.

Abstract: A developing device for developing a latent image formed on an image carrier of the present invention includes a rotatable, nonmagnetic developer carrier, and a magnetic field generating member for generating a magnetic field in a developing zone where the developer carrier faces the image carrier. The magnetic field generated causes a developer deposited on the developer carrier to rise in the form of a magnet brush. A magnetic pole for development is located upstream of a position where the developer carrier and image carrier are closest to each other in a direction of rotation. A magnetic force, as measured on the surface of the developer carrier, increases from the position of the magnetic pole toward a position where the magnet brush finally leaves the image carrier.

Abstract: A developer carrier for an SLIC developing system includes a developing sleeve and a magnetic roll having a plurality of magnetic poles. A narrow development nip is formed by narrowing the width of a development pole forming a magnet brush and by narrowing a developer rising region in a developing region where a flux density attenuation ratio of the development pole is 40% or more. A half-value width of the flux density of the development pole is 22° or less and the flux density variation rate is 4.0 mT/Deg or more in a circumferential direction in a part where the flux density in at least half of that of a downstream side of a developer carrying direction from a peak magnetic force position of the development pole is 90% or less.

Abstract: A developing roller, comprising a developing sleeve consisting of a nonmagnetic material, and a magnet roll provided inside the developing sleeve and formed by dispersing a magnetic powder in a polymer compound, the portion corresponding to the developing pole of the magnet roll being equipped with a main-pole molded magnet whose magnetic force per unit of volume is greater than that of the magnet roll, wherein the magnetic pole adjacent to the developing pole of the magnet roll downstream in the developer conveyance direction has a peak magnetic flux density on the developing sleeve equal to or greater than that of the developing pole, and has a half value width, which is the width of the magnetic pole at which a magnetic flux density of one-half the peak magnetic flux density is exhibited, is greater than that of the developing pole.

Abstract: A development magnet roller for use in a development roller of an electrophotographic image forming apparatus is provided. The development magnet roller has a development pole to form a magnetic field causing a developer born on a surface of the development roller including the development magnet roller to rise in a form of a series of ears in a development area of the image forming apparatus where the development roller opposes an image bearing member, and in a magnetic flux density distribution in a normal line direction of the development pole, a peak magnetic flux density is 120 mT or greater, a zero gauss region width is 70° or greater, and a half-value region width is 40° or smaller.

Abstract: The long magnet includes a magnet block made of a mixture of rare earth magnetic powder, thermoplastic resin particles, fluidity additive, pigment, wax and charge control agent, and a reinforcing member to reinforce the magnet block. At least part of the reinforcing member is arranged inside of the magnet block.

Abstract: A developer carrier used for an SLIC developing system. Characteristic values contributing to provide high image quality, which cannot be covered by the stipulations of the attenuation ratio and half-value width of the flux density are clarified. The developer carrier is constituted to be composed of the developing sleeve for carrying and transporting the developer, and a magnetic roll disposed in the developing sleeve, having a plurality of magnetic poles P1-P5. A narrow nip for development is realized by narrowing the width of the pole for development P1 forming the magnet brush by raising the developer in the developing region facing the latent image carrier, and by narrowing the rising region of the developer in the developing region and the flux density attenuation ratio of the pole for development P1 is 40% or more. The half-value width of the flux density of the pole for development P1 is 22% or less, and the flux density variation rate is 4.

Abstract: In a developing device for an image forming apparatus of the present invention, use is made of a magnetic molding produced by compression-molding a magnet compound material in a magnetic field. The magnet compound material contains, in addition to magnetic powder and fine, thermoplastic resin grains that are major components, at least one of a pigment and a charge control agent.

Abstract: A developing device for developing a latent image formed on an image carrier of the present invention includes a rotatable, nonmagnetic developer carrier, and a magnetic field generating member for generating a magnetic field in a developing zone where the developer carrier faces the image carrier. The magnetic field generated causes a developer deposited on the developer carrier to rise in the form of a magnet brush. A magnetic pole for development is located upstream of a position where the developer carrier and image carrier are closest to each other in a direction of rotation. A magnetic force, as measured on the surface of the developer carrier, increases from the position of the magnetic pole toward a position where the magnet brush finally leaves the image carrier.

Abstract: A developing device which prevents bias of a developer caused by an axial magnetic force of a magnet roller, and which can form an image uniform in the axial direction; and a magnet roller for a developing device which is used in the above developing device and is reduced in axial magnetic force. The developing device includes a rotatable sleeve which carries a developer on the surface thereof, a fixed magnet roller which is provided within the sleeve and has a plurality magnetic poles, and a doctor blade which controls the amount of developer carried on the sleeve. The developing device is constructed so that among the plurality of magnetic poles of the magnet roller, the ratio of the axial magnetic flux density to the radial magnetic flux density of a magnetic pole opposing the doctor blade is 2.5/100 or less in a central portion in the axial direction.