Toner and full-color image forming method

An image forming method, comprising:

• (A) an image forming cycle including:
• a step of forming an electrostatic image on an image bearing member,
• a step of developing the electrostatic image with a color toner to form a color toner image on the image bearing member, and
• a step of transferring the color toner image onto a transfer material via or without via an intermediate transfer member,
• (B) a process of repeating the image forming cycle (A) four times by using first to fourth color toners, respectively, to form superposed first to fourth color toner images on the transfer material, and
• (C) a step of fixing the superposed first to fourth color toner images on the transfer material under application of heat and pressure to form a fixed full-color image on the transfer material, wherein
• the first to fourth color toners are selected successively in an arbitrary order from the group consisting of a cyan toner, a magenta toner, a yellow toner and a black toner,
• each of the cyan, magenta, yellow and black toners comprises at least a binder resin, a wax and a corresponding colorant selected from the group consisting of a cyan colorant, a magenta colorant, a yellow colorant and a black colorant,
• the toner has viscoelasticity including:
• a storage modulus at 80° C. (G′80) in a range of 1×106-1×108 dN/m2, storage moduli at temperatures of 120-180° C. (G′120-180) in a range of 1×104-5×105 dN/m2 and loss tangents (tan δ=G″/G′ as a ratio between G″ (loss modulus) and G′ (storage molecules)) including a loss tangent at 180° C. (tan δ180) and a minimum of loss tangents over a temperature range of 120-180° C. (tan δmin) satisfying 1≦tan δ180/tan δmin,
• the toner exhibits a thermal behavior providing a heat-absorption curve according to differential scanning calorimetry (DSC) showing a maximum heat-absorption peak temperature in a range of 50-110° C. in a temperature range of 30-200° C., and
• the binder resin comprises a hybrid resin comprising a polyester unit and a vinyl copolymer unit.