Electrographic toner and process for preparation thereof

Claim 1

A process for preparing a toner composition comprising a polymer binder, a colorant, a charge-controlling agent and a dispersant which is useful for developing an electrostatically charged image in an electrophotographic method comprising: forming a composition comprising a monomer, a colorant, 0.1 to 10% by weight of a polymerization initiator based on the monomer, 0.5 to 5 percent by weight of a charge-controlling agent based on the toner and 5 to 300 percent by weight of a dispersant based on the charge-controlling agent, wherein said dispersant is selected from the group consisting of: (1) a higher fatty acid salt of a long-chain alkylamine or a long-chain hydroxyalkylamine having the formula (I): ##STR26## in which R1, R2, R3 and R4 are each a long-chain alkyl or alkenyl having 8 to 20 carbon atoms, a long-chain hydroxyalkyl or hydroxyalkenyl having 8 to 20 carbon atoms, a lower alkyl having 1 to 2 carbon atoms, a lower hydroxyalkyl having 1 to 2 carbon atoms or benzyl, with a proviso that one or two of R1, R2, R3 and R4 is the long-chain alkyl, the long-chain alkenyl, the long-chain hydroxyalkyl or the long-chain hydroxyalkenyl, and R5 is an alkyl or an alkenyl having 8 to 18 carbon atoms; (2) a polyoxyalkylenephenylether or a polyoxyalkylenealkylphenylether having the formula (V): ##STR27## in which R is hydrogen or an alkyl having 1 to 18 carbon atoms, A is an alkylene having 2 to 4 carbon atoms and n is an integer of 1 to 100; (3) a polyethylenemine and (4) a polyoxyalkylenephenylether derivative(s) or a polyoxyalkylene-alkylphenylether derivative(s) having the formulae (VI) or (VII), respectively: ##STR28## in which R is a hydrogen or an alkyl having 1 to 18 carbon atoms, R6 is hydrogen or methyl, A is an alkylene having 2 to 4 carbon atoms, 1 is an integer of 1 to 20, m is an integer of 1 to 5 and n is an integer of 1 to 100, stirring said composition to mix and disperse the colorant, polymerization initiator and charge-controlling agent in the monomer to form an oil phase, adding and dispersing the oil phase in an aqueous phase to form a polymerizable suspension composition, and heating and dispersion-polymerizing the polymerizable suspension composition to form the toner composition.