Kao Corporation

Kohei Katayama

Hiroki Kakiuchi

Eiji Shirai

Masahito Yamazaki

Akihiro Eida

Yasuhiro Hidaka

Hisakazu Tajima

Shogo Watanabe

Hideaki Kondo

Kouta Ijichi

A toner for electrophotography containing a resin binder containing a crystalline composite resin C and an amorphous polyester A and an ester wax, wherein the crystalline composite resin C is a resin containing a polycondensation resin component and a styrenic resin component, wherein the polycondensation resin component is obtained by polycondensing an alcohol component containing an aliphatic diol having 9 or more carbon atoms and 14 or less carbon atoms, and a carboxylic acid component containing an aliphatic dicarboxylic acid compound having 9 or more carbon atoms and 14 or less carbon atoms, wherein a mass ratio of the amorphous polyester A to the crystalline composite resin C (amorphous polyester A/crystalline composite resin C) is 60/40 or more and 95/5 or less, and wherein a mass ratio of the crystalline composite resin C to the ester wax (crystalline composite resin C/ester wax) is 0.5 or more and 9 or less. The toner for electrophotography of the present invention is suitably used in development of latent images or the like which is formed in electrostatic development method, electrostatic recording method, electrostatic printing method or the like.

Toner for electrophotography

A toner for electrophotography containing a resin binder containing a crystalline resin and an amorphous resin, and a releasing agent, wherein the crystalline resin contains a crystalline composite resin C containing a polycondensation resin component and a styrenic resin component, wherein the polycondensation resin component is obtained by polycondensing a specified alcohol component and a specified carboxylic acid component, and wherein the amorphous resin contains an amorphous composite resin AC containing a polycondensation resin component and a styrenic resin component, wherein the polycondensation resin component is obtained by polycondensing an alcohol component and a specified carboxylic acid component, and an amorphous polyester AP obtained by polycondensing an alcohol component and a specified carboxylic acid component, wherein a softening point of the amorphous polyester AP is higher than a softening point of the amorphous composite resin AC, wherein a difference in softening points between the amorphous polyester AP and the amorphous composite resin AC is 10&#xb0; C. or more and 50&#xb0; C. or less. The toner for electrophotography of the present invention is suitably used in development of latent images or the like which is formed in, for example, electrostatic development method, electrostatic recording method, electrostatic printing method or the like.

Electrophotography toner

A method for producing a positively chargeable toner, including: step 1: melt-kneading a toner raw material composition containing a resin binder, a positively chargeable charge control agent, and fine fluororesin particles, and a recycled powder; step 2: cooling a melt-kneaded mixture obtained in the step 1, and pulverizing a cooled mixture; and step 3: classifying a pulverized product obtained in the step 2, wherein the resin binder in the toner raw material composition contains 50% by mass or more of a polyester having a softening point of 125&#xb0; C. or higher and 170&#xb0; C. or lower. The positively chargeable toner obtainable by the method of the present invention is suitably used in developing latent images formed in, for example, an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like.

Method for producing positively chargeable toner

A toner containing a resin binder containing two kinds of polyesters having softening points that differ by 10&#xb0; C. or more, a colorant and a charge control agent, wherein the two kinds of polyesters contain a polyester A having a softening point of from 105&#xb0; to 140&#xb0; C. and a glass transition temperature of from 30&#xb0; to 55&#xb0; C., and a polyester B having a softening point of from 140&#xb0; to 170&#xb0; C. and a glass transition temperature of exceeding 55&#xb0; C. and 80&#xb0; C. or lower. The toner of the present invention is usable in, for example, development of latent images formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

Growing community of inventors

Wakayama, Japan

Kohei Katayama