| 摘要 |
PURPOSE:To provide a sharp distribution of electrostatic charge quantity and to obtain a high-grade image having no fogging even if a toner is reduced to smaller grain sizes by specifying the coefft. of fluctuation of the toner used for electrophotographic copying to <=15% and the coefft. of fluctuation of a carrier to <=20%. CONSTITUTION:The carrier having <=20% coefft. of fluctuation of the grain size distribution is used or said carrier and the toner having <=15%, more preferably <=10% coefft. of fluctuation are combined. The grain size of the carrier is preferably 30-80mum and the carrier is produced by sticking resin coated magnetic particles electrostatically to the surface of a polymer core material and dissolving or swelling the surface layer part of the core material or the resin coated magnetic particles by applying heat locally to the surface layer part thereof or by using a small amt. of org. solvent, thereby executing the heating treatment. The polymer core material is preferably the org. polymer particles having the sharp grain size distribution of 1-100mum; for example, a polystyrene resin particles, etc. The resin coated magnetic particles are prepd. by a method such as coating and drying of the resin soln. dissolved with a thermoplastic resin on the surfaces of the shuitable magnetic particles. Alloys, etc., of, for example, iron, copper, zinc, nickel, etc., are used for the magnetic material. |
