Patent ID: 6013402
Filing Date: 2000-01-11
Classification: G03G

Abstract:
A color toner, comprising (i) color toner particles containing at least a binder resin and a colorant and (ii) an external additive, wherein(a) the color toner has a weight-average particle diameter of 5 to 8 .mu.m and a number-average particle diameter of 4.5 to 7.5 .mu.m, and contains 5 to 40% by number of particles having a particle diameter of 4 .mu.m or less in the number distribution of the color toner and 7% by volume or less of particles having a particle diameter of 10.08 .mu.m or more in the volume distribution of the color toner,(b) an inorganic powder selected from the group consisting of a strontium titanate powder, a cerium oxide powder and a calcium titanate powder, and a hydrophobic fine alumina powder are externally added to the color toner particles as the external additives, the inorganic powder has a longitudinal average particle diameter of 0.2 to 2 .mu.m, and the hydrophobic fine alumina powder has a longitudinal average particle diameter of 0.005 to 0.1 .mu.m,(c) the binder resin is a polyester resin crosslinked by a crosslinking agent,(d) the color toner particles contain 0 to 20 mg/lg of a chloroform insoluble matter,(e) the color toner has a storage modulus (G'.sub.130) of 2.times.10.sup.3 to 2.times.10.sup.4 [dyn/cm.sup.2 ] at a temperature of 130.degree. C. and a storage modulus (G'.sub.170) of 5.times.10.sup.3 to 5.times.10.sup.4 [dyn/cm.sup.2 ] at a temperature of 170.degree. C., and a value of G'.sub.170 /G'.sub.130 is in the range of 0.25 to 10.