| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problems that conventional magnet rollers react to applied magnetic fields and deform due to the use of a ferromagnetic body powder during molding magnet pieces, thereby causing crack, etc., it is difficult to carry out continuous extrusion molding by rupture of molded articles, it is difficult to carry out lamination with sufficient accuracy by generation of meandering when laminating magnet pieces on a shaft periphery surface, which may result in image degradation, and in particular, when a ferromagnetic powder is used on the basis of a rare earth-based magnetic powder, conventional magnet rollers are very easy to react to applied magnetic fields and it is more difficult to carry out continuous extrusion molding, due to the high residual magnetic flux density, and so on. <P>SOLUTION: A magnet material composition for extrusion molding is used wherein, in a mixture based on a ferromagnetic powder and resin binder, the weight ratio of a ferromagnetic powder in the mixture is 50-95 wt.%, the melt viscosity of the mixture is 30-45 N×m, and the bending strength after molding is 150×10<SP>5</SP>-250×10<SP>5</SP>N/m<SP>2</SP>. <P>COPYRIGHT: (C)2010,JPO&INPIT |
