LONG-SIZED MAGNET MOLDED FORM AND ITS MANUFACTURING METHOD AND MAGNET ROLLER, DEVELOPER CARRIER, DEVELOPING DEVICE, PROCESS CARTRIDGE AND IMAGE FORMING DEVICE

PROBLEM TO BE SOLVED: To provide a long-sized magnet molded form having uniform magnet characteristics in the longitudinal direction as shown in a flux-density distribution shown in Fig. without the collapse of edges at both ends in the longitudinal direction and without falling-off of both ends in the longitudinal direction at a low cost. SOLUTION: In the long-sized magnet molded form 10, a magnet compound composed of magnet powder and thermoplastic-resin fine grains is compressively molded. In such a magnet molded form 10, the mean grain size of magnet powder at both ends 1 and 3 in the longitudinal direction of the long-sized magnet molded form 10 is larger than that of magnet powder in a section 2 excepting both ends 1 and 3 in the longitudinal direction of the long-sized magnet molded form 10. The mean grain size of magnet powder at both ends 1 and 3 in the longitudinal direction of the long-sized magnet molded form 10 is set preferably in 150 to 300 μm, and the mean grain size of magnet powder in the section 2 excepting both ends 1 and 3 in the longitudinal direction of the long-sized magnet molded form 10 is set preferably at a value less than 90 to 150 μm. COPYRIGHT: (C)2006,JPO&NCIPI