Abstract: A conductive roller includes: a core member including an outer surface along and about an axial line thereof; and a surface layer arranged along the outer surface of the core member. The surface layer includes a conductive portion, and a surface roughness imparting material in a form of particles dispersed in the conductive portion. An average particle size of the surface roughness imparting material is in a range of 6 micrometers or greater and less than 10 micrometers. The number of particles of the surface roughness imparting material per unit area of the surface layer is in a range of 3.5×105 particles per mm2 or greater and 7.5×105 particles per mm2 or less. An average thickness of the surface layer is in a range of 0.2 micrometers or greater and 5.5 micrometers or less.

Abstract: A conductive roller includes: a core member including an outer surface along and about an axial line thereof; and a surface layer arranged along the outer surface of the core member. The surface layer includes a conductive portion formed of a conductive resin composition, and a surface roughness imparting material in a form of particles dispersed in the conductive portion. An average particle size of the surface roughness imparting material is in a range of 6 micrometers or greater and 10 micrometers or less. The number of particles of the surface roughness imparting material per unit area of the surface layer is in a range of 1.0×104 particles per mm2 or greater and 2.0×106 particles per mm2 or less. An average thickness of the surface layer is in a range of 3.0 micrometers or greater and 15.0 micrometers or less.

Abstract: A charging roll includes a core, a rubber substrate arranged around the core, and a surface layer arranged around the rubber substrate. The surface layer includes a conductive matrix containing a base material formed of an insulator, and a conductive material dispersed in the base material, and particles of a surface roughness-imparting material dispersed in the conductive matrix. Each of the particles of the surface roughness-imparting material is formed of an insulator, is porous, and has a specific surface area of 8.7 m2/g or greater and 55 m2/g or less.

Abstract: An electrostatic photographic copying machine includes a photosensitive body having a photosensitive layer on its surface, a charging apparatus, a developing device and a transfer device arranged along a moving passage of the photosensitive body. An optical system projects an image of an original onto the surface of the charged photosensitive body, and a fixation apparatus fixes a transferred image onto copying paper.