| 摘要 |
PROBLEM TO BE SOLVED: To provide a rotation detector for correctly detecting the rotation angle of an output gear for a long period, a sheet feeder, and an image forming apparatus. SOLUTION: The image forming apparatus is provided with the sheet feeder 1. The sheet feeder 1 is provided with a sheet feeding cassette 2, a lifting member 4, a drive shaft 5, and the rotation detector 6. The rotation detector 6 is provided with the output gear coupled to the drive shaft 5. The output gear is provided with a gear body having teeth at an outer end, and an electrode holding member attached to the gear body to attach a rotating electrode, and rotatably disposed in a case 9. The electrode-holding member includes at least one thermoplastic resin selected from among POM, PA, PBT, PP, PE, ABS resin, PS, PPE, PC and PMMA. The gear body includes a material whose strength is higher than the strength of the thermoplastic resin for composing the electrode-holding member. COPYRIGHT: (C)2011,JPO&INPIT |
