Arakawa Kagaku Kogyo Kabushiki Kaisha

Toyo Ink Manufacturing Company

Nobuo Yamada

Osamu Oseto

Hirobumi Iemura

Nobuyuki Yoshimoto

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.

Low temperature electrophotographic toner composition comprising

An electrophotographic toner composition having excellent fixing property at a low temperature, offset resistance, blocking resistance and the like comprising a resin binder and a colorant dispersed in the resin binder wherein the resin binder contains a non-linear polyester resin comprising (a) a dicarboxylic acid as an acid component, (b) a rosin glycidyl ester, an esterificated diphenol and a dihydric alcohol having no phenyl ring as an alcohol component, and (c) a polycarboxylic acid having a valency of not less than 3 and/or a polyhydric alcohol having a valency of not less than 3 as a crosslinking component; the content of the rosin glycidyl ester is 5 to 50% by mole based on the component (b), the content of the etherificated diphenol is 20 to 95% by mole based on the component (b) and the component of the dihydric alcohol having no phenyl ring is 0 to 30% by mole based on the component (b); and the content of the component (c) is 0.5 to 20% by weight based on the polyester resin. A polyvalent metal compound may be used in the above polyester resin in order to improve electric properties in high moisture.

Growing community of inventors

Nara, Japan

Nobuo Yamada