PURPOSE: To prevent a photosensitive drum from being scraped and to prevent fogging based on nonuniformity on the thickness of the surface layer of an electrifying roller end part.
CONSTITUTION: A roller member 2B constituted of a roller substrate 2b and the surface layer 2c is formed in the periphery of a core bar 2a. Provided that the layer thickness within 10mm from the roller end part of the thickest part A is maximum layer thickness (a), the layer thickness of the thinnest part B is minimum layer thickness (b), and the layer thickness of an averaged part C in the center part is average layer thickness (c), respectively; these values are set to be 2(a-b)≤c so as to reduce ruggedness, so that the surface of the photosensitive drum is prevented from being scraped in the case a current is concentrated on the thin part B, and electrifying defectiveness in the case the volume resistance of the thick part A becomes high is prevented.
INOUE TAKAHIRO
KATO JUNICHI
OSHIMA MASAKI
SUWA KOICHI
ANDO ATSUTOSHI
SATO HIROSHI
SANO TETSUYA
INAMI SATOSHI
YAMAGUCHI SEISHI
