公开(公告)号：US20240142890A1

公开(公告)日：2024-05-02

申请号：US18273185

申请日：2021-12-03

Applicant: NOK CORPORATION

Inventor： Kosuke OURA ,  Norimasa HOSONUMA ,  Atsushi IKEDA ,  Yu AKAI ,  Satoshi FUKUOKA ,  Kenji SASAKI

IPC: G03G15/08

CPC classification number: G03G15/0808 ,  G03G15/0881

Abstract: A developing roll for use in an image-forming apparatus using electrophotography includes a cylindrical core made of metal; an annular elastic layer made of rubber and arranged around the core; and an annular surface layer arranged around the elastic layer. The surface layer includes a central portion and end portions. The central portion is located at the center of the developing roll in the longitudinal direction, the end portions are located at opposite end portions of the developing roll in the longitudinal direction. A coefficient of kinetic friction of the outer peripheral surface of each end portion of the surface layer is less than or equal to 0.1, and a ten-point average roughness Rz of the outer peripheral surface of each end portion of the surface layer is less than or equal to 1.8 μm.