PRODUCTION OF ANISOTROPIC MAGNET ROLL

摘要

PURPOSE:To produce an anisotropic magnet roll having sufficient magnetic characteristics by injection molding using relatively simple facilities. CONSTITUTION:An injection mold is provided with an even number of permanent magnets 3 and yokes 4 for a magnetic circuit. These magnets 3 are arranged along the periphery of a cavity 1 at a cross section of the mold vertical to a shaft to a magnet roll to be molded. The adjacent magnets 3 are in contact with each other at a position apart from the cavity 1. The yoke 4 is interposed between the same magnetic poles of the magnets 3 from said position to the periphery of the cavity 1. On the periphery of the cavity 1, a ratio of a central angle corresponding to an area occupied by the yoke 4 to a central angle corresponding to an area occupied by the magnet 3 is determined to 1/10-1/2.