Kao Corporation

Akihiro Eida

Jun Shimizu

Eiji Shirai

Takashi Kubo

Shinichi Sata

Hiroyuki Kawaji

Hisakazu Tajima

Koji Shimokusa

Yasuhiro Hidaka

Shogo Watanabe

Koji Kameyama

Takeshi Ashizawa

Kohei Katayama

A method for producing a toner including the steps of melt-kneading at least a resin binder and a colorant to give a kneaded product (step 1); and heat-treating the kneaded product obtained in the step 1 (step 2), wherein the resin binder contains a crystalline resin and an amorphous resin, wherein the crystalline resin contains a specified composite resin containing (a) a specified polycondensation resin component and (b) a styrenic resin component, in a specified weight ratio, wherein the composite resin is contained in the resin binder in a specified amount. The toner obtained by the above method is used in, for example, the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

Method for producing toner

A method for forming fixed images including the step of applying a toner for electrostatic image development containing at least a resin binder, a colorant, and a releasing agent to an apparatus for forming fixed images without a filter in a gas discharge part, wherein the resin binder contains a polyester, and wherein the releasing agent is a hydrocarbon-based wax, wherein the hydrocarbon-based wax has a melting point as determined by a differential scanning calorimeter of from 70&#xb0; to 85&#xb0; C., and contains components melting at a temperature equal to or lower than 65&#xb0; C. having an amount of heat absorption as determined by a differential scanning calorimeter of less than 7.5 J/g, and a toner for electrostatic image development used in a method for forming fixed images. The method for forming fixed images of the present invention is suitably used in the development of a latent image formed in, for example, electrophotography, electrostatic recording method, electrostatic printing method or the like.

Method for forming fixed images

A toner containing a resin binder and a colorant, wherein the resin binder contains a crystalline resin and an amorphous resin, the crystalline resin containing a composite resin containing: a polycondensation resin component obtained by polycondensing an alcohol component containing an aliphatic diol having 2 to 10 carbon atoms, and a carboxylic acid component containing an aromatic dicarboxylic acid compound, and a styrenic resin component, and the amorphous resin containing a polyester obtained from an alcohol component containing an aliphatic diol in an amount of 60% by mol or more, and a carboxylic acid component. The toner of the present invention is suitably used in, for example, the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

Toner and method for producing toner

A method for producing a toner, comprising the step of feeding raw materials containing a resin binder and a colorant to an open-roller type kneader, and melt-kneading the raw materials, wherein the resin binder contains a crystalline polyester and an amorphous polyester, and wherein the crystalline polyester and the amorphous polyester fed to the open-roller type kneader are in a weight ratio, i.e. crystalline polyester/amorphous polyester, of from 5/95 to 30/70, and have a ratio of average particle sizes of crystalline polyester/amorphous polyester of from 1.5 to 4.0. The toner obtained according to the present invention is used in, for example, the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

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.

Toner

A toner having a BET specific surface area of from 1.5 to 3.5 m/g, obtainable by a process including the steps of; step (1): pulverizing a toner composition containing at least a resin binder and a colorant in the presence of fine inorganic particles having an average primary particle size of from 6 to 20 nm to obtain mother toner particles having a volume-median particle size of from 3 to 8 &#x3bc;m; and step (2): externally adding silica having an average primary particle size of from 25 to 60 nm to the mother toner particles obtained in the above step (1). The toner of the present invention is suitably used for, for example, developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.

A method for producing a toner, including at least the following steps: step (A): pulverizing a negatively chargeable charge control resin that does not soften at a temperature of 180&#xb0; C. or lower to an average particle size of from 0.05 to 2 &#x3bc;m; step (B): melt-kneading at least a pulverized product of the negatively chargeable charge control resin obtained in the step (A), a resin binder, and a colorant; and step (C): pulverizing a melt-kneaded product obtained in the step (B) and classifying the pulverized product. The toner obtained according to the present invention is suitably used in, for example, the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

The present invention relates to a toner for electrostatic image development, obtainable by a process including the steps of:

Toner for electrostatic image development

A process for preparing a toner including the steps of (I) melt-kneading a raw material mixture containing a resin binder and a colorant; (II) cooling the melt-kneaded mixture obtained in the step (I) and pulverizing the cooled mixture to give a pulverized product having a volume-median particle size (Dv) of from 10 to 1000 &#x3bc;m; (III) pulverizing the pulverized product obtained in the step (II) in the presence of an external additive having an average particle size of from 8 to 50 nm; and (IV) classifying the pulverized product obtained in the step (III), wherein the resulting toner has a volume-median particle size (Dv) of from 3.5 to 8 &#x3bc;m, and the total amount of m kind(s) of external additive(s) in the step (III) satisfies a specified formula. The toner can be used, for instance, for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

Process for preparing toner

A process for preparing a toner including the steps of (I) melt-kneading a raw material mixture containing a resin binder, a wax, and a colorant with an open-roller type kneader; (II) cooling the melt-kneaded mixture obtained in the step (I) and pulverizing the cooled mixture; and (III) classifying the pulverized product obtained in the step (II) to give a toner, wherein the wax is contained in the toner in an amount of from 2 to 15% by weight, and has a number-average particle size in the toner of 1 &#x3bc;m or less, wherein the toner has a volume-median particle size (D) of from 3.5 to 7 &#x3bc;m, and a standard deviation in volume base particle size distribution of &#xbc; of Dor less, and contains 5% by volume or less of particles having particle sizes of (1.4&#xd7;D) &#x3bc;m or more, and 5% by number or less of particles having particle sizes of 3 &#x3bc;m or less. The toner can be used, for instance, for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

The present invention relates to a toner for electrostatic image development, obtainable by a process including the steps of (I) melt-kneading a raw material mixture comprising a resin binder, a releasing agent, and a colorant; cooling the melt-kneaded mixture; and pulverizing the cooled mixture; and (II) further pulverizing a pulverized product obtained in the step (I) in the presence of an external additive; and classifying the pulverized product, wherein the releasing agent in the step (I) contains a wax having a melting point of from 65&#xb0; to 100&#xb0; C., and wherein the external additive in the step (II) contains specified inorganic oxides. The toner of the present invention can be suitably used, for instance, for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

The present invention relates to a toner for electrostatic image development, obtainable by a process including the steps of (I) melt-kneading a raw material mixture containing a resin binder, a releasing agent, and a colorant; cooling the melt-kneaded mixture; and pulverizing the cooled mixture; and (II) further pulverizing a pulverized product obtained in the step (I) in the presence of an external additive containing at least two kinds of inorganic oxides subjected to hydrophobic treatment, having different average particle sizes from each other; and classifying the pulverized product, wherein the inorganic oxides subjected to hydrophobic treatment in the step (II) have an average particle size of 20 nm or less, and a difference in average particle size of 3 to 10 nm; and a process for preparing the toner. The toner of the present invention can be suitably used, for instance, for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

A black toner comprising a resin binder; and a black colorant comprising a composite oxide of two or more metals and at least one of a blue dye or pigment and a green dye or pigment. The 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.

Black toner

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 toner for electrophotography comprising Resin (A) and Resin (B), wherein Resin (A) comprises Resin (C) and a wax dispersed therein, wherein a difference between the softening point of Resin (C) and the melting point of the wax is within 20&deg; C., and the softening point of Resin (B) is higher than the softening point of Resin (C), which can be used for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing, toner jetting and the like.

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Wakayama, Japan

Akihiro Eida