Black toner with defined loss tangent

摘要

To provide a black toner having excellent charging property and transferring property against a severe environmental change. The black toner includes toner particle containing at least a binder resin, carbon black and a releasing agent, wherein: the toner particles have a weight-average particle diameter of 3.5 to 8.0 mum; total amount 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 mum or more is 0.915 to 0.960; loss tangent tandelta (10³ to 10⁴ Hz) of the toner is represented by the following expression: tandelta (10³ to 10⁴ Hz)<=0.0060 where the loss tangent tandelta is represented by epsilon''/epsilon' where epsilon'' denotes dielectric loss factor and epsilon' denotes dielectric constant, and tandelta (10³ to 10⁴ Hz) denotes the loss tangent in a frequency range of 10³ to 10⁴ Hz; and a ratio of tandelta (10⁵ Hz) to tandelta (5x10⁴ Hz) is represented by the following expression: 1.05<=TANdelta (10⁵ Hz)/tandelta (5x10⁴ Hz)<=1.40 where tandelta (10⁵ Hz) denotes loss tangent at the frequency of 10⁵ Hz and tandelta (5x10⁴ Hz) denotes loss tangent at the frequency of 5x10⁴ Hz.