| 摘要 |
PURPOSE:To prevent the electrostatic adhesion of a toner to a roller surface while attaining the low-temp. fixation of the toner and to improve electrostatic offset resistance and durability by regulating the softening point and triboelectrostatic charge quantity of resin fine particles to be stuck to base material particles by mechanical impact force. CONSTITUTION:The vinyl resin fine particles, the softening point of which is higher than the softening point of the binder resin incorporated into the base material particles and is <=160 deg.C and the absolute value of the negative triboelectrostatic charge quantity of which to iron powder is >=100muC/g are used as the resin fine particles to be fixed by the mechanical impact force to the surface of the base material particles contg. a resin consisting of crystalline polyester and amorphous vinyl polymer as the binder. Since the upper limit of the softening point of the resin fine particles is regulated to 160 deg., the surfaces of the resin fine particles soften and are liable to be fused to the surfaces of the base material particles. In addition, the lower limit of the absolute value of the negative triboelectrostatic charge quantity of the resin fine particles is regulated and, therefore, the triboelectrostatic chargeability and durability of the positively charged toner are improved. The electrostatic offset resistance and durability are improved in this way. |
