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: A developing roller includes a developing sleeve and a magnet roller disposed within the developing sleeve to attract developer to an outer surface of the developing sleeve by magnetic force. The outer surface of the developing sleeve has a plurality of recesses of circular or elliptic shape in plan view regularly or irregularly arranged therein so as not to overlap.

Abstract: A magnetic field generating member with high stiffness and small size, an image development device, a process cartridge and an image forming apparatus including the magnetic field generating member as well as a manufacturing method of the magnetic field generating member are provided where the magnetic field generating member includes a main body, a groove provided in the main body, an interposition member configured to be fitted in the groove of the main body and including a concave portion and a magnetic member as a long magnetic compact fixed into the concave portion of the interposition member.

Abstract: 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.

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: A method of manufacturing a hollow body having an external surface randomly provided with a large number of depressions is provided. The method includes providing the large number of depressions on the external surface of the hollow body. A profile curve of the external surface in a circumferential direction is obtained while rotating the hollow body. A frequency analysis is performed on the obtained profile curve. A quality of the hollow body is judged by comparing a result of the frequency analysis with a predetermined judgment standard.

Abstract: A magnetic roller includes a cylindrical magnetic field generation part (140), a cylindrical support part (143) that contacts both of the edges of the magnetic field generation part (140), further has a smaller diameter than the magnetic field generation part (140), and which is installed upon a common axis thereof as an axis of the cylindrical support part (143), and a depression part (140c) that is installed upon an obverse surface of the cylindrical magnetic field generation part (140), extends in a direction of the axis of the magnetic field generation part (140), and wherein a lengthwise magnet formation is inserted.

Abstract: An image forming device comprises a process cartridge. The process cartridge comprises a development roller. The development roller comprises a magnet roller and a developing sleeve 132. The magnet roller is fixed. The depressions 139 each having an oval shape are formed on the external surface of the developing sleeve 132. Both ends of the depressions 139 which are adjacent with each other along the longitudinal direction of the developing sleeve 132 are overlapped with each other and both ends of the depressions 139 which are adjacent with each other along the circumferential direction of the developing sleeve 132 are spaced with each other.

Abstract: A method of manufacturing a hollow body having an external surface randomly provided with a large number of depressions is provided. The method includes providing the large number of depressions on the external surface of the hollow body. A profile curve of the external surface in a circumferential direction is obtained while rotating the hollow body. A frequency analysis is performed on the obtained profile curve. A quality of the hollow body is judged by comparing a result of the frequency analysis with a predetermined judgment standard.

Abstract: 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.

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 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, a developer regulating member to regulate the thickness of a layer of the two-component developer. 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. The second magnetic pole generates a magnetic force to attract the developer to form a magnetic brush on the developer bearing member. The developer regulating member includes a magnetic member outwardly disposed on an exterior perimeter surface of the developer bearing member upstream from the developer regulating member, and one planar surface of the magnetic member faces the second magnetic pole across an effective development region.

Abstract: 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.

Abstract: A magnetic roller includes a cylindrical magnetic field generation part (140), a cylindrical support part (143) that contacts both of the edges of the magnetic field generation part (140), further has a smaller diameter than the magnetic field generation part (140), and which is installed upon a common axis thereof as an axis of the cylindrical support part (143), and a depression part (140c) that is installed upon an obverse surface of the cylindrical magnetic field generation part (140), extends in a direction of the axis of the magnetic field generation part (140), and wherein a lengthwise magnet formation is inserted.

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 magnetic field generating member with high stiffness and small size, an image development device, a process cartridge and an image forming apparatus including the magnetic field generating member as well as a manufacturing method of the magnetic field generating member are provided where the magnetic field generating member includes a main body, a groove provided in the main body, an interposition member configured to be fitted in the groove of the main body and including a concave portion and a magnetic member as a long magnetic compact fixed into the concave portion of the interposition member.

Abstract: A develop unit is configured to include a developer roller having a developer sleeve and a magnetic roller with a magnetic pole, a supply path formed in parallel with an axial direction of the developer roller, a supply screw supplying the developer to the developer roller, and a first bulkhead forming the supply path. In the developer unit, the magnetic pole is disposed so that a normal line through a maximum magnetic flux density point in a circumferential direction coincides with a tangent line to an upper portion of the supply screw in a rotary direction, the maximum magnetic flux density point being a point at which a density of a magnetic flux from the magnetic pole is maximum on an outer surface of the developer sleeve.

Abstract: A developing roller includes a developing sleeve and a magnet roller disposed within the developing sleeve to attract developer to an outer surface of the developing sleeve by magnetic force. The outer surface of the developing sleeve has a plurality of recesses of circular or elliptic shape in plan view regularly or irregularly arranged therein so as not to overlap.

Abstract: 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.

Abstract: A magnet roller for use with a hollow cylindrical structure made of a non-magnetic material includes a roller body and a reinforcing member. The roller body, encased in the hollow cylindrical structure, has at least one magnetic pole to form an agent releasing area on a skin of the cylindrical structure. The roller body is integrated with a shaft on each end portion of the roller body as one solid body. The reinforcing member is embedded in a portion of the roller body corresponding to the agent releasing area. The reinforcing member is made of a material different from a material used for the roller body and extends in an axial direction of the roller body.