| 摘要 |
PURPOSE:To prevent spent toners and to form the long-life carrier having stable electrostatic chargeability by sticking the fine particles of an insulating oxide to the surface of carrier nuclear particles, thereby forming the carrier for the dry process two-component developer. CONSTITUTION:The fine particles of the insulating oxide are stuck to the surface of the carrier nuclear particles and sintering is induced between the carrier nuclear particles and the fine particles of the insulating oxide by a heat treatment to stick the fine particles of the insulating oxide to the carrier surface. The fine particles of the oxide are formed by mixing and agitating the fine powder of SiO2, Al2O3, etc., having the average grain sizes of the prescribed values or below together with ferrite particles in a ball mill, etc. These particles are tribostatically charged to stick the fine particles of the insulating oxide to the ferrite particle surfaces and are subjected to the heat treatment, by which said particles are sintered and fixed. The carrier for the dry process two-component developer is formed by sticking the fine particles of the insulating oxide to the carrier nuclear particles by the heat treatment in such a manner, by which the dependency of the specific resistance of the carrier on electric fields is decreased and the fluidity of the carrier is greatly improved. |
