HELICAL GEARS FOR A PROCESS CARTRIDGE

摘要

A photosensitive drum for use in an image forming apparatus has a cylindrical member with a photosensitive layer thereon; a first gear provided at one end of said cylindrical member in an axial direction thereof; and a helical gear as a second gear provided at said one end of said cylindrical member adjacent to and outside of said first gear in the axial direction of said cylindrical member, said helical gear having a diameter larger than a diameter of said first gear. The helical gear meshes with a drive gear provided in a main body of the image forming apparatus to receive the drive force of a motor provided in the main body for rotating said photosensitive drum when said photosensitive drum is used for the image forming apparatus, and said first gear meshes with a gear of the transfer roller provided in the main body to transmit the drive force of said photosensitive drum to the transfer roller. The first gear and said helical gear are integrally formed as a gear portion, said integrally-formed gear portion comprising a through-bore portion having a first portion, and a second portion, said first portion being disposed outside of said second portion in the axial direction of said cylindrical member and having an inner diameter that is smaller than an inner diameter of said second portion, said first portion being fitted on a drum shaft when said photosensitive drum is mounted in the image forming apparatus. The drive force of the motor acts on a root portion of the shaft which supports one end of the photosensitive drum. Therefore, the inclination of the shaft can be reduced such that, when the photosensitive drum is rotated, it does not vibrate with respect to the shaft, allowing the drum to be smoothly rotated with high accuracy.