| 摘要 |
PURPOSE:To obtain a magnetic roll which has not cracking and possesses satisfactory linearity of magnetic power by a method wherein nonmagnetic shaft, of which main body is resin whose melting point is equal or higher than the melting point of resin for injection molding. CONSTITUTION:Injection molding is performed to a nonmagnetic resinous shaft 2, using resin such as polycarbonate and the like whose melting point is equal or higher then melting point of moldings resin and using resin which is filled up by reinforcing agent such as carbonfiber, glass powder and the like at need, so that the difference of coefficient of linear expansion alphaT between the titled item and a moldings. The molding of a resinous magnet 1 is obtained by performing injection molding to a metallic mold which is inserted by the shaft 2, adding magnetic field with the use of resin such as polyamide and the like mixed with ferrite powder. As difference alphaT between the shaft 2 and a resinous magnet 1 is small, cracking is not generated. Then, a magnetic roll, which possesses satisfactory linearity of magnetic power, can be obtained by means that compounding volume of magnetic powder is 80-96wt%. |
