Kao Corporation

Jun Shimizu

Masayuki Maruta

Akihiro Eida

Shinichi Sata

Yasuhiro Hidaka

Shin-ichi Sata

Yoshihiro Fukushima

Koji Shimokusa

Masayoshi Nawa

Hidenori Tachi

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

Toner for electrostatic image development

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 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 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 full color toner for nonmagnetic one-component development usable in a developer device including a developer roller and a blade, the blade serving to regulate a toner layer formed on the developer roller into a uniform thickness and to supply electric charges to toners by triboelectric charging, the full color toner for nonmagnetic one-component development including (a) fine resinous particles including at least a colorant and a binder resin having a polyester resin as a main component; and (b) additives externally applied onto a surface of the fine resinous particles, the additives including inorganic fine particles consisting of positively chargeable, inorganic fine particles and negatively chargeable, inorganic fine particles when subjecting the additives to triboelectric charging with an iron powder.

Full color toner for nonmagnetic one-component development

Toner for electrophotography and reinforcing agent for said toner

The positively chargeable toner used for a nonmagnetic one-component developing method includes a toner particle and fine polytetrafluoroethylene particles, the toner particle having (a) a binder resin having a polyester resin having an acid value of 10 mg KOH/g or less; (b) a colorant; and (c) a charge control agent, and the fine polytetrafluoroethylene particles, whose average primary particle size is at least 0.05 .mu.m and less than 0.5 .mu.m, being externally added to the surface of the toner particle. The nonmagnetic one-component developing method includes the step of loading the above positively chargeable toner in a developer device for a nonmagnetic one-component toner.

Positively chargeable toner for nonmagnetic one-component developing

The nonmagnetic one-component toner is usable in a developer device including a developer roller and a blade, the blade serving to regulate a toner layer formed on the developer roller into a uniform thickness and to supply electric charges to the toner by triboelectric charging, and the nonmagnetic one-component toner includes at least a binder resin, a colorant, and an iron compound. Here, the binder resin includes a polyester resin as a main component, and the iron compound has the general formula (I) and is contained in an amount of between 0.1 parts by weight or more and less than 1.0 part by weight, based on 100 parts by weight of the binder resin.

Nonmagnetic one-component toner

The present invention relates to an eletrophotographic carrier characterized by that the surface thereof is coated and cured with a partially hydrolyzed sol obtained from at least one alkoxide selected from the group consisting of silicon alkoxides, titanium alkoxides, aluminum alkoxides and zirconium alkoxides, and the production process therefor. Use of the carrier of the present invention mixed with a toner to prepare a developer can always supply a stable image without a coated layer being peeled off during use.

Electrophotographic carrier and production process therefor

A developer composition for an electrostatic charge image, which comprises a toner comprising a binder resin and a coloring agent, and 0.1 to 1.0% by weight of fine polymer particles with a glass transition temperature of 90.degree. C. or higher deposited on the surface of the toner, the binder resin comprising, as a main component, a polyester resin with an OHV/AV value of 1.2 or more wherein OHV and AV represent the hydroxyl value and acid value of the polyester resin, respectively.

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Wakayama, Japan

Jun Shimizu