Patent ID: 8198000

Claim:
A method for producing a toner having a volume average particle diameter (dv) between 7.3 and 8.1 μm and a ratio of volume average particle diameter (dv)/number average particle diameter (dp) not larger than 1.3, the method comprising the steps of: (1) dispersing a water-soluble polyvinyl alcohol having a degree of polymerization of 1,900 to 2,100 and a degree of saponification of 85 to 95% in an aqueous medium to prepare an aqueous dispersion comprising 1 to 10 parts by weight of the polyvinyl alcohol based on 100 parts by weight of the aqueous dispersion; (2) preparing a mixture of monomers; (3) mixing the aqueous dispersion with the monomer mixture in order to include 0.1 to 20 parts by weight of the above polyvinyl alcohol based on the total weight of all monomers used; (4) suspension polymerizing the monomers while applying a shear force to the mixed solution of the above aqueous dispersion and the above monomer mixture using a homogenizer; and (5) removing the above polyvinyl alcohol, wherein 1 to 60 parts by weight of the monomer mixture is mixed with 100 parts by weight of the aqueous dispersion, the monomer mixture includes 30 to 95 parts by weight of an aromatic vinyl monomer based on 100 parts by weight of all monomers used; 5 to 70 parts by weight of at least one monomer selected from the group consisting of acrylate, methacrylate and diene monomers based on 100 parts by weight of all monomers used; 1 to 20 parts by weight of a pigment based on 100 parts by weight of all monomers used; 0.1 to 30 parts by weight of a wax based on 100 parts by weight of all monomers used; 0.001 to 10 parts by weight of a crosslinking agent based on 100 parts by weight of all monomers used; 0.1 to 20 parts by weight of a charge control agent based on 100 parts by weight of all monomers used; 0.001 to 8 parts by weight of a molecular weight modifier based on 100 parts by weight of all monomers used; wherein the monomer mixture further includes 0.01 to 10 parts by weight of at least one polar polymer selected from the group consisting of polyesters and styrene-acrylate polymers, based on 100 parts by weight of the monomer mixture without the polar polymer, and wherein the monomer mixture further includes 0.1 to 30 parts by weight of an acidic or basic olefin monomer, based on 100 parts by weight of all monomers used.