Toyo Ink Manufacturing Company

Arakawa Kagaku Kogyo Kabushiki Kaisha

Nobuyuki Yoshimoto

Osamu Oseto

Nobuo Yamada

Hirobumi Iemura

A toner composition for electrophotography excellent in fixing property at a low temperature, offset resistance and blocking resistance comprising a resin binder and a colorant which is dispersed in the resin binder, the resin binder being a nonlinear polyester resin prepared by the reaction of: (a) an acid component comprising at least one long chain dicarboxylic acid selected from the group consisting of a linear aliphatic dicarboxylic acid having 16 to 34 carbon atoms, a dimer acid and a dibasic acid having 21 carbon atoms, an aromatic dicarboxylic acid, and optionally a monocarboxylic acid, (b) an alcohol component comprising an etherificated diphenol and optionally a glycidyl ester of rosin and (c) a crosslinking component comprising a polycarboxylic acid having valency of not less than 3 and/or a polyhydric alcohol having a valency of not less than 3, wherein in case that the long chain dicarboxylic acid and the aliphatic dicarboxylic acid are employed, the contents of the long chain dicarboxylic acid and the aromatic dicarboxylic acid are 2 to 25% by mole and 75 to 98% by mole, respectively and in case that the long chain dicarboxylic acid, the aliphatic dicarboxylic acid and the monocarboxylic acid are employed, the contents of the long chain dicarboxylic acid, the aliphatic dicarboxylic acid and the monocarboxylic acid are 2 to 25% by mole, 10 to 93% by mole and 5 to 65% by mole, respectively, based upon the total amount of the (a) acid component, the content of the (c) crosslinking component is 0.5 to 20% by weight of the polyester resin, and an organic polyvalent metal compound is contained in an amount of 0 to 40% by weight based upon the polyester resin.

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Kawagoe, Japan

Nobuyuki Yoshimoto