| 摘要 |
PURPOSE: To eliminate adverse influence by the abrasion of a developing roller and to form a stable image by constituting a toner carrier of an inner layer consisting of an elastic body and a surface layer having magnetism and forming a non-magnetic part whose one part is laid on the end of the inner layer at both ends of the surface layer. CONSTITUTION: The developing roller 13 is constituted of a core bar 18, the inner layer 19 consisting of the elastic body and provided around the core bar 18, and the surface layer 20 having the magnetism and provided around the inner layer 19. A part excepting the non-magnetic parts 21 and 22 at both parts of the surface layer 20 is a magnetic field generating part 23. The magnetic field generating part 23 is an area where magnetic poles are arranged on the surface layer 20, and the non-magnetic parts 21 and 22 are areas where the magnetic poles are not arranged. The length of the surface layer 20 is set the same as the length of the inner layer 19, whereby the non-magnetic parts 21 and 22 are arranged at both ends of the inner layer 19. Furthermore, toner seals 27 and 28 are arranged at both ends of the developing roller 13, and the non-magnetic parts 21 and 22 are included in areas on which the toner seals 27 and 28 abut. |
