| 摘要 |
PURPOSE:To obtain a spherical and strong carrier for developing agent having superior surface smoothness by forming a coating layer of a polymer consisting essentially of a positively chargeable monomer on a carrier core for the developing agent. CONSTITUTION:After heating a mixture of a carrier material consisting essentially of a resin and magnetic powder, the material is sprayed directly as it is melted, and cooled with air stream at relatively low temp. Thus, spherical particles having high surface smoothness and high strength are obtained. A coating layer of a copolymer consisting essentially of a positively chargeable monomer is formed on said particles as core. Examples for the suitable component of the copolymer are styrene, methyl styrene, dimethyl styrene, conjugated dienic aliphatic diolefin such as 3-methyl-2,4-hexadiene, etc. By this method, high surface smoothness of a carrier is obtd., coating of a charge controlling polymer is facilitated, and the chargeability is stabilized. |
