Class / Patent application number | Description | Number of patent applications / Date published |
399277000 | Magnet | 37 |
20080213006 | DEVELOPING DEVICE, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS - A developing device is disclosed. The developing device includes a developing roller disposed to face an image carrier and a toner carrier capturing roller disposed to face the developing roller for capturing toner carriers adhered onto the image carrier. The developing roller generates a magnetic pole at a side facing the toner carrier capturing roller. A first virtual line, which connects a rotational center of the developing roller to a rotational center of the toner carrier capturing roller, passes through a region between a position where a magnetic flux density of the magnetic pole in the normal line direction is minimum on the developing roller at the upstream side in the rotational direction of the developing roller and a position where the magnetic flux density of the magnetic pole in the normal line direction is maximum on the developing roller. | 09-04-2008 |
20080213007 | MAGNET ROLLER AND METHOD FOR THE SAME, MAGNETIC PARTICLE-SUPPORT MEMBER, DEVELOPMENT DEVICE, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS - 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. | 09-04-2008 |
20080226355 | DEVELOPMENT DEVICE, PROCESS CARTRIDGE, AND IMAGE FORMATION APPARATUS - 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. | 09-18-2008 |
20080232861 | DEVELOPMENT DEVICE AND IMAGE FORMING APPARATUS - The development device of this invention includes a developer bearing member, a magnet, and a developer regulation member. The magnet is fixedly disposed within the interior of the developer bearing member. The developer regulation member includes at least a magnetic member. And the thickness of this magnetic member along the rotational direction of the developer bearing member is between 0.2 mm and 0.4 mm inclusive. Moreover, if the distance over the developer bearing member, from the position thereupon which the center of the magnetic member along the rotational direction opposes, to the position thereupon at which the magnetism of that magnetic pole which is disposed closest to that position is a maximum, is termed L (mm), and the diameter of the developer bearing member is termed D (mm), then the magnetic member is disposed within the range in which the relationship 0≦L/D≦0.044 holds. | 09-25-2008 |
20080240795 | Developing Device Used In An Image Forming Apparatus - The developing device | 10-02-2008 |
20080298849 | Magnetic roller and manufacturing method thereof, developer carrier, development device, processing cartridge, and image forming apparatus - A magnetic roller includes a solid-core roller having magnetic anisotropy in a direction orthogonal to a central axis thereof. The solid-core roller includes a body part, and shaft parts disposed on both ends of the body part, a concave groove provided in an outer circumference face of the body part to extend in an axial direction, and a magnetic block disposed in the concave groove, the magnetic block having a direction of magnetic anisotropy substantially orthogonal to a direction of the magnetic anisotropy of the magnetic roller. | 12-04-2008 |
20080298850 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS HAVING THE SAME - A developing device and an image forming apparatus capable of restraining density irregularity and restraining a decline in image quality caused by adherence of carrier to a photoreceptor, are provided. An angle α is in a range of no less than 45 degrees nor more than 57 degrees, which is formed between a plane comprising a central line of magnetic pole formed by a regulating pole in a magnet roller and a rotating central axis of a developing sleeve and a plane comprising a central line of magnetic pole formed by a pumping pole and a rotating central axis of the developing sleeve. Further, an absolute value of the maximum value of strength of the magnetic pole formed by a main pole is in a range of no less than 120 mT nor more than 140 mT. | 12-04-2008 |
20080304873 | DEVELOPING UNIT AND IMAGE FORMING APPARATUS EMPLOYING THE SAME - A developing unit which forms an image on a photosensitive medium, includes a housing which accommodates a developer, a magnetic cylinder having a catch pole which picks up the developer in the housing by a magnetic force, and a main pole which couples a carrier among the picked-up developer, a sleeve rotatably installed on a circumference of the magnetic cylinder to form a magnetic brush having a predetermined width on the circumference by the developer picked up by the catch pole, and a sealing member provided at opposite end parts in an axial direction of the sleeve to prevent a leak of the developer, wherein a width W | 12-11-2008 |
20090041510 | IMAGE FORMING APPARATUS - An image forming apparatus is provided containing an image bearing member, a developer bearing member, and a developer control member being magnetic. The electrostatic latent image on the image bearing member is developed with a toner to form a toner image. The carrier includes magnetic core particles having a cover layer on the surfaces thereof, including fine particles having a weight average particle diameter of from 0.02 to 0.5 μm. The carrier has a weight average particle diameter of from 22 to 32 μm, and a ratio (E10/E100) of from 1.00 to 1.20. The ratio (E10/E100) is a ratio of a total energy (E10) to a total energy (E100) at a leading edge speed of the blade of 10 mm/s and 100 mm/s, respectively, measured using a power rheometer at an angle of approach of −5°. | 02-12-2009 |
20090148196 | MAGNET KNIFE ASSEMBLY FOR A TONER DEVELOPING DEVICE - A magnet knife assembly for a toner developing device including a ferromagnetic strip held between like poles (N) of two permanent magnets such that a knife edge portion of the strip projects outwardly beyond the two magnets and is subject to a magnet force that tends to urge the strip in a direction in which the knife edge projects further out of the magnets, wherein the length of the strip is selected such that a portion of the strip opposite to the knife edge is subject to a magnetic force that at least counterbalances said magnetic force on the knife edge portion. | 06-11-2009 |
20090245889 | DEVELOPING UNIT, IMAGE FORMING APPARATUS INCORPORATING SAME, AND PROCESS CARTRIDGE INCLUDING SAME - A developing unit includable in a process cartridge and in an image forming apparatus includes a developer bearing member including a magnetic field generator and a nonmagnetic hollow member, a developer container, an agitation/conveyance member, and a developer regulating member. The magnetic field generator has first and second magnetic poles to generate respective magnetic forces for removing the developer from the developer bearing member after the developer passes the development region. A developer-releasing region releases the developer from the developer bearing member using a release force. The developer is disposed higher than a surface of the developer in the developer storing chamber. A component of a magnetic flux density of the magnetic field generated by the magnetic field generator in a direction normal to the developer-releasing region is directed to a same direction as the first and second magnetic poles across the developer-releasing region without forming a local maximum point. | 10-01-2009 |
20090274489 | DEVELOPING APPARATUS USABLE WITH IMAGE FORMING APPARATUS, IMAGE FORMING APPARATUS HAVING THE SAME, METHOD TO PREVENT DEVELOPER FROM FLOWING OUT THE DEVELOPING APPARATUS - A developing apparatus usable with an image forming apparatus includes a developer carrier includes a plurality of magnetic poles and a case to rotatably support the developer carrier, the case storing developer is supplied to the developer carrier, and a magnetic pole changing apparatus disposed at an end of the developer carrier to change a position of the plurality of magnetic poles with respect to the case. | 11-05-2009 |
20090290913 | DEVELOPING DEVICE, IMAGE FORMING APPARATUS AND DEVELOPING ROLLER - Described is a developing roller, which makes it possible to appropriately peel developer off the developing roller, even if the developing roller is a small-sized. The developing roller includes a non-magnetic developing sleeve and a magnetic member installed into an inner space of the developing sleeve and having plural magnetic poles including a peeling magnetic pole. When a reference position is defined as such a position that exhibits a maximum value of magnetic flux density to be generated in a normal direction by the peeling magnetic pole, a magnetic-flux density flat region within which the magnetic flux density is kept at substantially a constant value being closely approximate to the maximum value of the magnetic flux density and the reference position is included, exists while fulfilling an Equation indicated as follow: | 11-26-2009 |
20090311011 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS - The present invention provides a developing device which is capable of suppressing the generation of a fogging phenomenon and deposition of carrier particles to an electrostatic latent image carrier and developing the electrostatic latent image efficiently, the device comprising a development sleeve and a magnet body onto which the sleeve is fitted, and using a two-component developer. An angular position which indicates the peak value of the magnetic flux density in the normal direction produced by a development pole of the magnet body is shifted downstream from the center position of the development pole in the direction of movement of the surface of a photosensitive member in a development region. The present invention also provides an image forming apparatus which can form high-quality images with reduced noise such as fogging by mounting the developing device. | 12-17-2009 |
20100067959 | DEVELOPER CARRIER, DEVELOPMENT DEVICE, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS - A developer carrier includes a magnetic field generating device provided with a plurality of magnetic poles including an agent separating pole and a scooping pole, and a cylindrical hollow body accommodating therein the magnetic field generating device and rotated around an axis of the cylindrical hollow body. A half-value width of a magnetic flux density at both end portions of at least one magnetic pole of the agent separating pole and the scooping pole is formed to be identical to or narrower than a half-value width of the magnetic flux density at a central portion of the one magnetic pole. | 03-18-2010 |
20100104329 | MAGNETIC CARRIER, TWO COMPONENT DEVELOPER, DEVELOPING DEVICE, IMAGE FORMING APPARATUS, AND IMAGE FORMING METHOD - Regarding a magnetic carrier of the present invention, a surface of a magnetic core material is coated with a coating layer containing electrically conductive particles and a charge control agent composed of same components as components of a charge control agent contained in a electrophotographic toner. Further, the magnetic carrier exhibits an electric resistance value of 8.22×10 | 04-29-2010 |
20100178082 | Developing Device and Process Cartridge and Imaged Forming Device Provided with them - Object: To prevent trailing and leading to enable excellent development with a simple constitution. | 07-15-2010 |
20100202805 | DEVELOPMENT DEVICE, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS - A development device includes a developer containing part containing two-component developer, a cylindrical developer carrier to carry by rotation the developer to a development range, a first developer transport member disposed in the developer containing part, to supply the developer to the developer carrier while transporting the developer in an axial direction of the developer carrier, and a magnetic field generator disposed inside the developer carrier, having three developer-carrying magnetic poles, consisting of a development pole to generate a first magnetic field in the development range, a pre-development pole to generate a second magnetic field to transport the developer supplied from the developer containing part to the development range, and a post-development pole to generate a third magnetic field disposed between the first magnetic field and the second magnetic field, to transport the developer to a release position where the developer is separated from the developer carrier. | 08-12-2010 |
20100290820 | DEVELOPMENT DEVICE AND IMAGE FORMING APPARATUS USING THE SAME - Provided is a development device and an image forming apparatus both using a hybrid development method and capable of forming high quality images without occurrence of development hysteresis (ghost). The nip portion of the toner carrier and the developer carrier is configured as follows: the rotating direction of a toner carrier and a developer carrier are in counter directions; a magnetic pole facing the toner carrier is positioned on the upstream side in the developer carrier rotating direction; and a counter charge generated by the toner supply reaches a toner recovering portion without being considerably attenuated. | 11-18-2010 |
20110044730 | DEVELOPING DEVICE AND ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS INCLUDING THE DEVELOPING DEVICE - A developing device and an electrophotographic image forming apparatus are disclosed. The developing device includes a ferromagnetic member arranged to cover at least partially the outer circumferences of two repulsive magnets of a developing roller so as to form a separating portion from which the developing agent remaining residual on the developing roller is released. | 02-24-2011 |
20110150539 | DEVELOPMENT DEVICE AND IMAGE FORMING APPARATUS HAVING THE SAME - The development device includes a developer storage part storing a developer, a developer carrier having a carrying surface for carrying the developer and a first magnet, and receiving the developer from the developer storage part on the carrying surface while rotating in a predetermined direction, and supplying the developer to a predetermined image carrier, a magnetic member formed from a magnetic material, forming a predetermined regulatory gap with the carrying surface, and arranged opposite to the first magnet, a second magnet disposed more upstream than the magnetic member when viewed from the rotating direction of the developer carrier, and having a magnetic pole of the same polarity as the first magnet, and a deterioration suppressing part suppressing deterioration of the developer transported to the regulatory gap along with the rotation of the developer carrier. | 06-23-2011 |
20110262190 | MAGNET ROLLER, DEVELOPER HOLDER ELEMENT, DEVELOP UNIT, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS - A magnet roller includes a magnetic field generator being columnar, a support element being columnar, coaxially provided at both ends of the magnetic field generator, and whose diameter is smaller than that of the magnetic field generator, a level element extending along an axis of the magnetic field generator with a distance from the axis, the distance larger than the diameter of the support element, and a high magnetic power element being a main magnetic pole provided on the level element, extending long along the axis of the magnetic field generator. | 10-27-2011 |
20130004209 | DEVELOPING DEVICE, IMAGE FORMING APPARATUS, AND PROCESS CARTRIDGE - A developing device including a developer container and a developer bearing member is provided. The developer container contains a two-component developer comprising toner particles and magnetic carrier particles having a ten-point average surface roughness Rz of 0.5 to 3.0 μm. The developer bearing member is a cylindrical member containing a magnetic field generator having multiple magnetic poles. The developer bearing member is adapted to bear the two-component developer on a surface thereof and to convey the two-component developer as the surface rotates. The developer bearing member has a ten-point average surface roughness Rz of 10 to 30 μm. The multiple magnetic poles include three developer bearing poles each adapted to generate a magnetic field having a strength enough for retaining the two-component developer on a surface of the developer bearing member. The three developer bearing poles consist of a developing pole, a pre-developing pole, and a post-developing pole. | 01-03-2013 |
20130051865 | MAGNET ROLLER - A magnet roller according to the present invention comprises: a single metal shaft member; and a pair of first and second semicylindrical resin magnet members each of which is shorter than the metal shaft member and has a first or second annular portion integrally provided at one end portion thereof. Each of first and second central holes is provided at the center of each of the first and second annular portions. The magnet roller according to the present invention is assembled by arranging the first annular portion and the second annular portion so as not face each other, inserting both end portions of the metal shaft member into the first and second central holes from the inner side of the first and second annular portions, and sandwiching the metal shaft member between the first and second semicylindrical resin magnet members in such a manner that both the end portions of the metal shaft member protrude to the outside of the first and second annular portions. | 02-28-2013 |
20130149012 | MAGNET ROLL - A magnet roll for development for a printer, a copying machine, or the like. The magnet roll comprises a metal pipe provided with recesses formed on a surface thereof and portion maintaining an original metal surface, and a magnet inserted into the metal pipe. Recesses on the surface of the metal pipe are formed by etching using a resist formed by an inkjet process, and irregularities based on crystal grains of metal are formed on an inner surface of each of the recesses and can effectively carry toner that is carried by carrier to a portion of latent images. | 06-13-2013 |
20130236216 | MAGNET ROLLER, DEVELOPER BEARER, DEVELOPMENT DEVICE, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS - A magnet roller includes a roller-shaped body constructed of a magnetic field generating material, a first support rod provided to a first axial end of the body; and a second support rod provided to a second axial end of the body. At least one of the first and second support rods is constructed of a nonmagnetic material and includes a projecting part projecting outside the body from an end face of the body and a buried part united to the projecting part and positioned inside the body. The buried part includes a reduced-area portion smaller than a base end of the projecting part adjacent to the buried part in cross-sectional area perpendicular to an axial direction of the first and second support rods. | 09-12-2013 |
20130279946 | IMAGE FORMING APPARATUS - An image forming apparatus includes an image carrier, a developing unit, and a developer sucking section. A relationship 0≦X≦R+kRW (where k=10 to 12) is established, when X (m) is a distance from a center of a transport pole to a position where a straight line crosses a rotating section, R (m) is a chain standing length of developer on the transport pole, W (m/s) is a peripheral velocity of the developing unit, and k is a coefficient. The transport pole is adjacent to a development pole and is situated downstream of the development pole in a direction of rotation of the rotating section. The straight line is situated at a downstream side in the direction of rotation of the rotating section and connects a center of rotation of the developing unit and an end of the developer sucking section. | 10-24-2013 |
20140029986 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS - A developing device includes a developing member including a magnet member on which plural magnetic poles including a developing main magnetic pole are magnetized in a circumferential direction and a developer holder that faces an image supporting member, receives the magnet member, and holds a developer, wherein the distribution of a magnetic attraction force in a circumferential direction has a gradient that increases toward a downstream end from an upstream end of a developing area in a developer transport direction of the developer holder, and the magnetic poles are magnetized on the magnet member so that the amount of the increase of the magnetic attraction force between the upstream end and a middle position of the developing area is larger than that between the middle position and the downstream end. | 01-30-2014 |
20140056622 | DEVELOPMENT DEVICE AND IMAGE FORMING APPARATUS INCORPORATING SAME - A developing device to develop a latent image includes a developer bearer including a rotatable, hollow developer supporter to carry two-component developer on a surface thereof, and a stationary magnetic field generator having multiple magnetic poles and disposed inside the hollow developer supporter, and a magnetic field adjuster. The magnetic field generator generates a magnetic flux on the surface of the hollow developer supporter, and the magnetic field adjuster suppresses a maximum value of magnetic flux density in a tangential direction to the surface of the hollow developer supporter from a predetermined value for image formation. | 02-27-2014 |
20140147177 | DEVELOPMENT ROLLER AND IMAGE FORMING APPARATUS INCLUDING DEVELOPMENT ROLLER - A development roller according to the present invention includes a magnet roller in which a magnet portion generating a magnetic force and a shaft portion projecting from the magnet portion are formed integrally, wherein a recess is provided on an end surface of the magnet portion on a side of the shaft portion. | 05-29-2014 |
20140286681 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS - A developing device includes a sleeve and a magnet roller having first and second magnetic poles, the second magnetic pole being disposed downstream of the first magnetic pole. A magnetic attraction distribution on the sleeve in a region from the first magnetic pole to the second magnetic pole is such that the magnetic attraction decreases from a position of the first magnetic pole toward the downstream side, a gradient of change in the magnetic attraction decreases in a region downstream of a region in which a gradient of reduction in the magnetic attraction temporarily increases, thereby forming an attraction reduction region in which the magnetic attraction is reduced so that developer cannot be held on the sleeve, and the gradient of change in the magnetic attraction increases in a region downstream of the attraction reduction region so that the magnetic attraction increases to a position of the second magnetic pole. | 09-25-2014 |
20140356032 | DEVELOPING ROLLER, DEVELOPING DEVICE, AND IMAGE FORMING APPARATUS - A developing roller includes a cylindrical transporting member and a magnet member. The transporting member is disposed so as to rotate with a gap being disposed between the transporting member and a latent image carrying member that rotates. The transporting member carries and transports magnetic developer, and is formed of a nonmagnetic material. The magnet member is disposed with multiple magnetic poles being fixed in a cylindrical interior of the transporting member. In the developing roller, multiple magnetic members are disposed in a regular arrangement at a carrying surface of the transporting member that carries the developer. | 12-04-2014 |
20150023701 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS HAVING THE SAME - A developing device includes a magnetic roller, a developing roller, a cover, a first magnetic force generator, a second magnetic force generator with a different polarity, and a movement controller. A roller surface of the magnetic roller holds toner and magnetic carrier, the toner being adhered to the magnetic carrier. The developing roller is arranged to face the magnetic roller. The first magnetic force generator is provided inside the magnetic roller such that a magnetic pole face thereof faces the developing roller. The second magnetic force generator is provided inside the developing roller so as to be able to move between a first position and a second position. A magnetic pole face of the second magnetic force generator faces the magnetic roller at the first position and faces the cover at the second position. The movement controller causes the second magnetic force generator to move between positions. | 01-22-2015 |
20150071686 | Method and Apparatus for Magnetic Brush Retraction in Electrophotographic System - A method and apparatus for retracting a magnetic brush in an imaging device. The apparatus includes a housing containing carrier beads and toner particles; a magnetic structure at least partly disposed within the housing and generating at least one magnetic field; and an endless sleeve disposed around and rotatable about the magnetic structure, at least a portion of the sleeve extending from the housing. During toner development, the magnetic structure is in a first position for developing a magnetic brush of the carrier beads and toner particles along the portion of the sleeve extending from the housing which forms a developer nip with a photoconductor, and during a period of time when toner development is not to be performed, the magnetic structure is in a second position for retracting the magnetic to brush by causing the carrier beads to be positioned against the portion of the endless sleeve extending from the housing forming the developer nip. | 03-12-2015 |
20150086247 | DEVELOPING DEVICE AND IMAGE FORMING APPARATUS - There are provided a developing device capable of preventing occurrence of image unevenness by releasing a developer residing on a surface of a developing roller reliably, and an image forming apparatus. An angle α formed by a first plane including a position at which a magnetic flux density in a normal direction by a removing pole becomes a maximal value on a surface of the developing sleeve and a rotational axis of a developing sleeve, and a second plane including a first axis of a first rotational shaft section of a first agitating conveyance section and the rotational axis of the developing sleeve | 03-26-2015 |
20160041505 | DEVELOPING APPARATUS - A developing apparatus includes a developer carrying member configured to carry a developer, and a magnet member disposed inside the developer carrying member. The magnet member includes one or more first magnet portions having a first magnetic polarity at an outer surface thereof opposing an inner surface of the developer carrying member, and one or more second magnet portions having a second magnetic polarity at an outer surface thereof opposing the inner surface. In a cross-section perpendicular to a longitudinal direction of the magnet member at a longitudinally central portion thereof, a number of the first magnet portions is larger than a number of the second magnet portions, and a ratio of a total area of the first magnet portions in the cross-section is smaller at a longitudinally end portion of the magnet member than at the longitudinally central portion. | 02-11-2016 |
20180024468 | DEVELOPING APPARATUS, PROCESS CARTRIDGE, AND IMAGE FORMING APPARATUS | 01-25-2018 |