Kao Corporation

Shinichi Sata

Nobumichi Kamiyoshi

Yoshinobu Ishikawa

Eiji Shirai

Takashi Mukai

Jun Shimizu

Yasuhiro Hidaka

Koji Shimokusa

Hiroshi Mizuhata

Masayuki Maruta

Takehiro Tsutsumi

Akihiro Eida

Takashi Yamaguchi

Yoshihiro Ueno

Hiroyuki Kawaji

Yuuta Matsumoto

Yoshiaki Ban

Toshihiro Hattori

Hironobu Nagasaki

Yoshifumi Tokuhisa

The present invention relates to a process for producing a toner for electrophotography which is excellent in dispersibility of a colorant in the toner and capable of considerably improving an image density, as well as a toner for electrophotography which is produced by the process. There is provided a process for producing a toner for electrophotography which includes the step of mixing a dispersion of colorant-containing polymer particles with a dispersion of resin particles containing substantially no colorant to aggregate the colorant-containing polymer particles and the resin particles, wherein the polymer contains a constitutional unit derived from a salt-forming group-containing monomer (a) and a constitutional unit derived from an aromatic ring-containing monomer (b).

Process for producing toner for electrophotography

The present invention relates to a polyester for thermal transfer image-receiving sheets which includes a polyester A produced from an alcohol component containing 50 mol % or more of an alkyleneoxide adduct of 2,2-bis(4-hydroxyphenyl)propane and an acid component containing 80 mol % or more of an aliphatic carboxylic acid and/or an alicyclic carboxylic acid as a total amount thereof, and a polyester B produced from an alcohol component containing 80 mol % or more of the alkyleneoxide adduct of 2,2-bis(4-hydroxyphenyl)propane and an acid component containing 10 to 35 mol % of a trivalent or higher valent aromatic polycarboxylic acid; a resin dispersion containing the polyester; a process for producing the resin dispersion; a thermal transfer image-receiving sheet using the polyester; and a process for producing the thermal transfer image-receiving sheet. The thermal transfer image-receiving sheet is capable of satisfying all of a dyeability, a light resistance and a releasability at the same time.

Polyesters for thermal transfer image-receiving sheets

The present invention relates to a dye receptor layer composition for thermal transfer image-receiving sheets which includes (a) a resin dispersion containing a polyester-containing resin, (b) a glycol ether having a boiling point of from 160&#xb0; C. to 280&#xb0; C. and a vapor pressure at 20&#xb0; C. of from 20 to 1,000 Pa and (c) an oxazoline group-containing compound, and is excellent in film-forming property; and a thermal transfer image-receiving sheet obtained from the composition which can be dried at a low temperature for a short period of time, exhibits a low heat fusibility, is excellent in releasability, printing sensitivity and imaging performance, and can produce images with a high density.

Dye receptor layer compositions

The present invention relates to a resin emulsion which has a good emulsification performance even when produced by using a crosslinked polyester resin as a binder resin, and also is capable of producing a toner having an excellent storage property therefrom; and a process for producing the resin emulsion. The process for producing a resin emulsion according to the present invention, includes the steps of: (a) mixing a resin containing a polyester having at least one constitutional unit selected from the group consisting of a constitutional unit derived from a trivalent or higher-valent alcohol component and a constitutional unit derived from a trivalent or higher-valent carboxylic acid component, an anionic surfactant, a nonionic surfactant and an aqueous medium with each other at a temperature not lower than a softening temperature (Ts) of the resin as measured by a flow tester method, the nonionic surfactant and the aqueous medium being used in amounts of from 0.1 to 1.0 part by weight and from 10 to 50 parts by weight, respectively, on the basis of 100 parts by weight of the resin; and (b) neutralizing a mixture obtained in the step (a) with a basic compound in an aqueous medium at a temperature not higher than a softening point (T) of the resin as measured by a flow tester method.

Method for production of resin emulsion

The present invention relates to a dye receiving layer composition for thermal transfer image-receiving sheets which includes a resin containing a polyester produced by using an alcohol component containing 50 mol % or more of an alkyleneoxide adduct of 2,2-bis(4-hydroxyphenyl)propane and an oxazoline group-containing compound. There are provided a composition for a dye receiving layer of a thermal transfer image-receiving sheet which is excellent in not only dyeability upon thermal transfer but also releasability from a transfer sheet, and a thermal transfer image-receiving sheet having a dye receiving layer obtained from the above composition which is capable of obtaining transferred images having excellent properties.

Dye receiving layer compositions for thermal transfer image-receiving sheets

The present invention relates to a process for preparing a toner for electrophotography containing a resin binder and a colorant, including the step of preparing fine particles of the resin binder to have a volume-median particle size (D) of from 0.05 to 3 &#x3bc;m in an aqueous medium in the presence of a nonionic surfactant within a temperature range of from 10&#xb0; C. below to 10&#xb0; C. above a cloud point of the nonionic surfactant; and a toner for electrophotography obtained by the process as defined above, wherein the toner contains 60% by weight or more of a crystalline polyester and has a volume-median particle size (D) of from 1 to 7 &#x3bc;m. The toner obtained according to the process of the present invention can be suitably used, for example, in development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.

Process for preparing toner for electrophotography

The present invention relates to a process for producing a resin emulsion which includes the steps of (a) dispersing a resin containing acidic group in a basic aqueous medium at a temperature lower than a softening point of the resin; (b) neutralizing a dispersion obtained in the step (a) at a temperature not lower than a glass transition point of the resin and not higher than the softening point of the resin; and (c) adding an aqueous liquid to the dispersion neutralized in the step (b) at the temperature not lower than the glass transition point of the resin and not higher than the softening point of the resin to emulsify the resin in the aqueous medium. According to the present invention, the resin emulsion suitably usable for production of a toner for electrophotography can be efficiently produced without using an organic solvent and a special apparatus.

Process for producing a resin emulsion and toner

A toner for electrostatic image development, comprising a resin binder comprising a crystalline polyester; a releasing agent comprising a wax having a melting point of from 60 to 85&#xb0; C. and a penetration at 25&#xb0; C. of from 4 to 10; and a colorant. The toner for electrostatic image development can be used, for instance, for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

Toner for electrostatic image development

A toner for electrophotography containing a resin binder and a colorant, wherein the resin binder contains a polyester in an amount higher than 50% by weight of the resin binder, wherein the polyester is obtained by polycondensing an alcohol component containing 60% by mol or more of an aliphatic diol having 3 to 10 carbon atoms and a carboxylic acid component comprising 80% by mol or more of an aromatic dicarboxylic acid compound, the polyester having an index of crystallinity of from 0.6 to 1.5, and a glass transition temperature of 0&#xb0; C. or more and less than 40&#xb0; C. The toner for electrophotography of the present invention can be used for, for example, developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.

Toner for electrophotography

The present invention relates to a process for producing a toner which includes the steps of emulsifying a resin binder containing a polyester in an aqueous medium to prepare an emulsion of the resin binder and adding a water-soluble nitrogen-containing compound having a molecular weight of 350 or less to the emulsion obtained in the previous step to aggregate emulsified particles contained in the emulsion. According to the present invention, the shape of toner particles can be controlled simply for a short production time by using a resin binder containing a polyester and using substantially no organic solvent, and further a toner having a narrow and sharp particle size distribution can be produced.

Process for producing a toner

A process for preparing a toner for electrophotography comprising a resin binder and a colorant, including the steps of (1) forming primary particles containing the resin binder and the colorant in an aqueous medium in the presence of a nonionic surfactant; and (2) aggregating the primary particles, and unifying the aggregated particle; and a toner for electrophotography obtainable by the process defined above, containing a crystalline polyester in an amount of 60% by weight or more in the toner, wherein the toner has a volume-median particle size (D) of from 1 to 7 &#x3bc;m. The toner for electrophotography obtained by the present invention can be suitably used in, for example, development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.

A nonmagnetic black toner comprising a resin binder, a black colorant comprising a metal oxide, and externally-added fine particles having an average particle size of 20 nm to 2.1 &#x3bc;m, wherein the fine particles are contained in the toner in an amount of 0.2% by weight or more. The nonmagnetic black toner can be used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

Nonmagnetic black toner

A nonmagnetic black toner comprising a resin binder; and a clorant comprising a composite oxide of two or more metals, wherein the toner has a viscosity at its softening point of from 4.5&#xd7;10to 2.3&#xd7;10Pa&#xb7;s. The nonmagnetic black toner can be suitably used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

A nonmagnetic black toner for reversal development comprising a resin binder; and a black colorant comprising a composite oxide of two or more metals, the composite oxide having an oil absorption per unit area of 0.07 ml/m or less. The nonmagnetic black toner can be suitably used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

Nonmagnetic black toner for reversal development

A yellow toner comprising fine resin particles and an external additive being added to surfaces of the fine resin particles, wherein the fine resin particles comprise (a) a resin binder comprising a polyester obtained by polycondensing an alcohol component comprising a compound represented by the formula (I), with a carboxylic acid component comprising a dicarboxylic acid compound and a tricarboxylic or higher polycarboxylic acid compound; (b) a colorant comprising a compound represented by the formula (II); and (c) a charge control agent comprising a compound selected from the group consisting of metal compounds of a salicylic acid derivative represented by the formula (III); and metal compounds of a benzilic acid derivative represented by the formula (IV); and wherein the external additive comprises silica having an average particle size of from 35 to 350 nm.

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Wakayama, Japan

Shinichi Sata