| 摘要 |
PURPOSE:To provide a plastic magnet roll having a high magnetic flux density by injecting or extruding a mixture of magnetic material and polymer while applying a magnetic pattern for a magnetic brush roll, forming a recess in the part for the developer pole of the magnet roll, and performing anisotropic treatment. CONSTITUTION:A composition containing ferrite particles and polymer is kneaded, and it is subjected to injection molding or extrusion molding in a magnetic field to form a magnet roll 2 having an easy axis of magnetization of the ferrite particles in a given orientation. During the molding, the roll is provided with a recess 3 in its periphery while the easy axis of the magnetic material is oriented into a magnetic pattern corresponding to the repulsion pole. According to this method, a magnet roll is manufactured at lower cost with improved productivity compared with the sintered magnet roll or plastic roll. |
