| 摘要 |
PURPOSE:To efficiently mass-produce a lightweight magnetic grain excellent in strength and durability and excellent in the characteristic as a carrier such as magnetic characteristic, charging characteristic and charging stability. CONSTITUTION:A magnetic layer 2, in which magnetic-substance fine grains 20 are aggregated, and a resin coat layer 3 are laminated on the surface of a core 1 in this order to constitute a magnetic grain. The grain is produced by dispersing the core 1 having an anionic group on the surface and the fine grains 20 in an aq. dispersion medium under neutral or alkaline conditions, acidifying the dispersion system to aggregate the grains 20 to form the magnetic layer 2 on the core 1 surface and then adding a polymerizable monomer which is polymerized to form the resin coat layer 3. |
