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 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 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: 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.