| 摘要 |
<p>PURPOSE:To prolong a service life without decreasing the picture density or occurring while void by using a binder resin of specified copolymer and subjecting a toner fine powder obtd. by kneading and pulverizing the binder resin, magnetic material and additives to surface modifying treatment. CONSTITUTION:The binder resin consists of copolymers expressed by formula I and formula II and has 1X10<4>-5X10<5> (poise) melt viscosity at 135 deg.C and 3X10<3>-3X10<5> (poise) melt viscosity at 145 deg.C. The binder resin, magnetic material and additives are kneaded and pulverized to obtain a toner fine powder, to which an external additive is added. Then the toner fine powder in a dispersed state is treated with hot air for surface modification so that fixing of the external additive, coating of the magnetic material and forming of spheric toner powder particles are simultaneously and instantaneously performed. In formulae, R1 is H or CH3, R2 is H or alkyl group of 1-5 carbon number, and R3 is H or alkyl group of 1-20 carbon number.</p> |
