MAGNET ROLLER, MANUFACTURING METHOD THEREOF, DEVELOPING ROLLER, DEVELOPING DEVICE, AND IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a magnet roller which can be manufactured by injection molding and is available for higher-speed printing in an electrophotographic image forming apparatus, and a developing roller, a developing device, and an image forming apparatus which include the magnet roller.SOLUTION: A magnet roller 10 includes a substantially column-shaped roller body 12. The roller body 12 has a draft taper 125 formed from a first end surface 121 to a second end surface 122. However, the draft taper 125 is not formed in a part including a main magnetic pole in a circumferential direction of the roller body 12. The magnet roller 10 is stored in a sleeve so that a distance between this part and the sleeve is constant, and the sleeve is rotatably supported, whereby the developing roller is constituted. The developing roller is mounted in the developing device and is used in the image forming apparatus.