Toner for developing electrostatic charge image and method for preparing the same

A method for preparing a toner, which comprises a binder resin, for developing an electrostatic charge image, the method comprising:

• dehydro-condensing a polycarboxylic acid component and a polyol component in a temperature of 150° C. or less under the presence of a catalyst to provide a condensed amorphous resin;
• urethane-extending the condensed amorphous resin to synthesize the amorphous polyester resin;
• forming a latex of the amorphous polyester resin;
• dehydro-condensing an aliphatic polycarboxylic acid component and an aliphatic polyol component in a temperature of 100° C. or less under the presence of a catalyst to provide a crystalline polyester resin;
• forming a latex of the crystalline polyester resin;
• mixing the amorphous polyester resin latex and the crystalline polyester resin latex to form a mixture;
• adding a flocculant comprising elemental iron and elemental silicon into the mixture;
• aggregating the amorphous polyester resin and the crystalline polyester resin to form a primary aggregated particle;
• disposing a coating layer comprising the amorphous polyester resin on a surface of the primary aggregated particle to form a coated aggregated particle;
• and
• fusing and coalescing the coated aggregated particle in a temperature that is greater than a glass transition temperature of the amorphous polyester resin to form the toner,
• wherein
• (1) a mole ratio of an aromatic portion of the amorphous polyester resin to an aliphatic portion of the amorphous polyester resin is in a range of 4.5 to 5.8,
• (2) a glass transition temperature of the amorphous polyester resin, when measured by a differential scanning calorimetry, is in a range of 50 to 70° C., and
• (3) an endothermic gradient in the glass transition temperature is in a range of 0.1 to 1.0 W/g° C., and
• wherein crystalline polyester resin comprises elemental sulfur and elemental fluorine, and
• (a) an endotherm in the melting of the crystalline polyester resin, when measured by the differential scanning calorimetry, is in a range of 2.0 to 10.0 W/g,
• (b) a weight average molecular weight of the crystalline polyester resin is in a range of 5,000 to 15,000 Daltons,
• (c) a difference between an endothermic start temperature and an endothermic peak temperature of the crystalline polyester resin is in range of 3 to 5° C. when the temperature of the crystalline polyester resin is increased in the differential scanning calorimetry curve determined by the differential scanning calorimetry, and
• (d) a content of the crystalline polyester resin having a weight average molecular weight of 1,000 Daltons or less which is in a range of 1 to less than 10%, based on a total content of the crystalline polyester resin, and
• wherein the catalyst comprises elemental sulfur.