| 摘要 |
PURPOSE:To improve chargeability of carrier for a two component developing agent and to enlarge an allowable width of the toner density by forming a resin coated layer comprising thermally fused first resin powder on the surface of the resinous carrier and fixing second resin powder on the resin coated layer. CONSTITUTION:First resin powder 2 having <=4mum particle size and <=1kg/mm<2> compressive strength is adhered to the surface of a spherical resin carrier 1 prepd. by dispersing magnetic powder, and the resin powder 2 is fused thermally to obtain thus a resin coated later 3 comprising the powder 2. After depositing second resin powder 4 having <=4mum particle size and 0.5-1.5 times mean particle size and >=10kg/mm<2> compressive strength for >=80wt.% of the whole particles onto the layer 3, the powder 4 is fixed by fusing thermally the layer 3. A styrenic copolymer, etc. may be used for a binder resin of the carrier 1, poly(meth)acrylic ester, etc. may be used for the powder 2, and benzoguanamine resin, etc. may be used for the powder 4. |
