Patent ID: 8750768

Claim:
A magnet roller that forms a magnetic pattern around the roller and processes a charged material based on the magnetic pattern, wherein the magnet roller comprises: a single metal shaft member; and a pair of first and second semicylindrical resin magnet members each of which is shorter than the metal shaft member and has a first or second annular portion integrally provided at one end portion thereof, each of first and second central holes is provided at the center of each of the first and second annular portions, the first annular portion and the second annular portion are arranged so as not to face each other, and the magnet roller is assembled by sandwiching the metal shaft member between the first and second semicylindrical resin magnet members in such a manner that both end portions of the metal shaft member are inserted into the first and second central holes from the inner side of the first and second annular portions and protruded toward the outside of the first and second annular portions.