Kao Corporation

Koji Shimokusa

Koji Akiyama

Shinichi Sata

Hiroshi Mizuhata

Koji Kameyama

Nobumichi Kamiyoshi

Takashi Yamaguchi

Kuniyasu Kawabe

Akihiro Eida

Shoichi Murata

Shingo Tanaka

Hiroyuki Kawaji

Jun Shimizu

Tetsuya Ueno

Yasuhiro Hidaka

Takayuki Ikenaga

Ikuo Takahashi

Takashi Okuno

Koji Nishibuchi

Yasuhiro Shidahara

Keishi Yokota

Yoshio Yoshimura

Shuji Watanabe

Manato Ikeda

Kojiro Kameyama

According to the present invention, there are provided a process for producing a toner for development of electrostatic images which is capable of suppressing desorption and exposure of a releasing agent therein, and excellent in fusing property, suppression of toner cloud and durability; a process for producing a dispersion, and a kit for producing the dispersion. The present invention relates to a process for producing a toner for development of electrostatic images which includes the following steps (1) to (3): step (1) of mixing and emulsifying a releasing agent and a dispersion of resin particles (A) containing a polyester in an amount of not less than 90% by mass on the basis of a resin component in the resin particles (A) to obtain a dispersion of releasing agent particles; step (2) of mixing and aggregating the dispersion of the releasing agent particles obtained in the step (1) and a dispersion of resin particles (B) containing a polyester in an amount of not less than 90% by mass on the basis of a resin component in the resin particles (B) to obtain aggregated particles; and step (3) of coalescing the aggregated particles obtained in the step (2) to obtain coalesced particles, in which an acid component constituting the polyester in the resin particles (A) contains an aliphatic carboxylic acid; the resin particles (A) have a volume median particle size of not less than 0.02 &#x3bc;m and not more than 0.50 &#x3bc;m; and a content of a surfactant in the dispersion of the releasing agent particles is not more than 0.5 part by mass on the basis of 100 parts by mass of the releasing agent; a process for producing the dispersion of the releasing agent particles which includes the above step (1); and a kit for producing the dispersion of the releasing agent particles.

Process for manufacturing toner for developing electrostatic image

The present invention relates to a process for producing a toner for electrophotography which is capable of suppressing liberation of a wax from a resin binder and exposure of the wax to a surface of respective toner particles in the step of obtaining fused particles upon production of the toner, and reducing a content of fine powders in the toner, and which is characterized by an excellent low-temperature fusing property and an excellent anti-high-temperature offset property. The process for producing a toner for electrophotography according to the present invention includes the following steps 1 to 3: Step 1 of mixing and emulsifying a wax, a resin emulsion containing a resin having an acid value of from 10 to 300 mgKOH/g, and an oxazoline group-containing polymer with each other to obtain a water dispersion of releasing agent particles; Step 2 of mixing and aggregating the water dispersion of the releasing agent particles obtained in the step 1 with a water dispersion of resin particles containing a carboxyl group-containing resin binder to obtain aggregated particles; and Step 3 of fusing the aggregated particles obtained in the step 2 to obtain fused particles.

Process for producing electrophotographic toner

The present invention relates to a process for producing a toner for electrophotography which includes the step of fusing aggregated particles containing resin particles (A) and releasing agent particles in an aqueous mixed solution containing the aggregated particles and an anionic surfactant having a polyalkylene glycol moiety with an average molar number of addition of an alkylene oxide having 2 to 3 carbon atoms of from 5 to 100 after and/or while adjusting a pH value of the aqueous mixed solution to 2.0 to 6.0 as measured at 25&#xb0; C., and a toner for electrophotography obtained by the process.

Process for producing toner for electrophotography

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 preparing a toner for electrophotography comprising a crystalline polyester and a colorant, wherein the colorant is added in at least one of the neutralizing step, the emulsifying step, and the aggregating step and a process for preparing a toner for electrophotography comprising a crystalline polyester and a colorant, wherein the colorant is added in at least one of the neutralizing and emulsifying step, and the aggregating step. 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

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 fixing apparatus for fixing visible images formed on a recording medium has a heat roller having a heating member in the inner portion of the heat roller, and a flat plate-like elastic member forming a nip in contact with the heat roller and capable of exerting a pressure at the nip portion by an elastic stress, the recording medium being fed into the nip portion. According to the fixing apparatus and the fixing method using this apparatus, since a pressure roller is not necessary, the system can be simplified, which leads to miniaturization of the overall fixing apparatus, reduction of overall weight and cost reduction.

Fixing apparatus and fixing method using the same

The encapsulated toner for heat-and-pressure fixing of the present invention having a heat-fusible core material containing at least a thermoplastic resin and a shell formed thereon so as to cover the surface of the core material is produced by the method having the steps of (a) dispersing in a shell-forming resin an additive selected from the group consisting of conductive materials, charge control agents, wax components, color pigments, particulate magnetic materials, and mixtures thereof to give a shell-forming resin containing the additive; (b) dissolving the shell-forming resin containing the additive in a mixture containing a core material-constituting monomer; (c) dispersing the mixture obtained in step (b) in an aqueous dispersant, and localizing the shell-forming resin containing the additive on the surface of droplets of the core-constituting material to give a polymerizable composition; and (d) polymerizing the polymerizable composition obtained in step (c) by in situ polymerization to form the core material, the shell in which the additive is dispersed covering the surface of the core material, whereby an encapsulated is formed.

Method for producing encapsulated toner for heat-and-pressure fixing and

The encapsulated toner for heat-and-pressure fixing of the present invention has a heat-fusible core material containing at least a thermoplastic resin and a coloring agent and a shell formed thereon so as to cover the surface of the core material. Moreover, the encapsulated toner has the following properties: 1) The glass transition temperature ascribed to the thermoplastic resin used as a main component of the heat-fusible core material is 10.degree. C. to 50.degree. C.; 2) A minimum load required for 58 compression of a particle size of the encapsulated toner is from 5 to 50 mgf, and a minimum load required for 10% compression of a particle size of the encapsulated toner is from 10 to 100 mgf, when a compressive variation of one toner particle is measured by a micro compression testing machine under the given conditions; and 3) The difference in cohesiveness before and after keeping the toner standing at 50.degree. C. for 24 hours, is not more than 10, wherein the cohesiveness is defined as the sum of values (a), (b), and (c) obtained by the following equations:

Encapsulated toner for heat-and-pressure fixing

An electrophotographic developer composition for flash fusing containing at least a binder resin based on a polyester resin and a colorant, the polyester resin being formed between an acid component, not less than 80 mol % of the acid component being phthalic acid series dicarboxylic acid and an alcohol component, not less than 80 mol % of the alcohol component being bisphenol A alkylene oxide adduct, the polyester resin having an acid value of not more than 10.0 KOH mg/g, a softening temperature of not less than 95.0.degree. C. and not more than 125.0.degree. C. as determined using a flow tester of the 'koka-shiki' type and a glass transition temperature of not less than 50.0.degree. C. and not more than 80.0.degree. C. as determined by DSC, whereby substantially no odor is produced upon flash fusing.

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Wakayama, Japan

Koji Shimokusa