Patent ID: 7300733

Claim:
A black toner comprising toner particles containing at least a binder resin, carbon black and a releasing agent, wherein: the toner particle has weight-average particle diameter of 3.5 to 8.0 um; total value of acid value and hydroxyl value of the toner is 30 to 75 mgKOH/g; average circularity of particles contained in the toner having circle-equivalent diameter of 2 μm or more is 0.915 to 0.960; loss tangent tan δ (10 3 to 10 4 Hz) of the toner is represented by the following expression: tan δ (10 3 to 10 4 Hz)≦0.0060 where the loss tangent tan δ is represented by ε″/ε′ where ε″ denotes dielectric loss factor and ε′ denotes dielectric constant, and tan δ (10 3 to 10 4 Hz) denotes the loss tangent in a frequency range of 10 3 to 10 4 Hz; a ratio of tan δ (10 5 Hz) to tan δ (5×10 4 Hz) is represented by the following expression: 1.05≦tan δ (10 5 Hz)/tan δ (5×10 4 Hz)≦1.40 where tan δ (10 5 Hz) denotes loss tangent at the frequency of 10 5 Hz and tan δ (5×10 4 Hz) denotes loss tangent at the frequency of 5×10 4 Hz; and wherein the binder resin is a mixture of a polyester resin, a hybrid resin component having a polyester resin unit and a vinyl polymer unit, and a vinyl polymer.