Patent ID: 7262262

Claim:
A toner comprising a colorant and a resin composition which consists essentially of a polyester block copolymer consisting of a crystalline polyester segment having a melting point of 140 to 280° C. and a non-crystalline polyester segment having a glass transition point of 30 to 80° C.; which has a storage modulus G depicted in Pa unit, when subjected to a dynamic viscoelasticity test under a condition involving a frequent of 15.92 Hz, a strain of 1%, a temperature of 60 to 300° C. and a temperature elevation rate of 10° C./minute, fulfilling either of the requirement (a), (b) or (c): (a) when X is assumed to be a constant value selected from an actual number of 1 or more and less than 10, then the range of the temperature fulfilling the requirement defined by the following formula (1) is present over at least 20° C. or more; (b) when X is assumed to be a constant value selected from an actual number of 1 or more and less than 10, then the range of the temperature fulfilling the requirement defined by the following formula (2) is present over at least 20° C. or more; then cooled rapidly to 0° C. at the temperature descending rate of 50° C./minute or more to delete the thermal hysteresis preliminarily then heated again at the temperature elevating rate of 10° C./minute to measure the differential calorie of the crystalline polyester resin, then the endothermic calorie (Sa) of the crystal melting endothermic peak per unit resin weight of the crystalline polyester resin is calculated from the peak area of the crystal melting endothermic peak, and then said polyester block copolymer is heated to a temperature higher slightly than the melting point at the temperature elevating rate of 10° C./minute using a differential scanning calorimeter then cooled rapidly to 0° C. at the temperature descending rate of 50° C./minute or more to delete the thermal hysteresis preliminarily then measured again the differential calorie of the polyester block copolymer at the temperature elevating rate of 10° C./minute, while the resin weight of the crystalline polyester segment in said copolymer is calculated from the resin weight of the polyester block copolymer used in the measurement then the endothermic calorie (Sb) of the crystal melting endothermic peak per unit resin weight of the crystalline polyester segment is calculated from the crystal melting endothermic peak area of the crystal part of said copolymer.