Kao Corporation

Koji Kameyama

Koji Akiyama

Masahito Yamazaki

Koji Shimokusa

Kuniyasu Kawabe

Hiroyuki Kawaji

Eiji Shirai

Nobumichi Kamiyoshi

Mitsuhiro Sasaki

Hiroshi Mizuhata

Akihiro Eida

Takashi Yamaguchi

Shoichi Murata

Takayuki Ikenaga

Shin-ichiro Yasuda

Yutaka Kanamaru

Takashi Okuno

Kouhei Katayama

Keishi Yokota

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

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 containing a resin binder, a charge control agent, and a colorant, and wherein the charge control agent contains a metal complex of a salicylic acid compound and a quaternary ammonium salt of a carboxylic acid. The toner for electrostatic image development of the present invention is suitably used in, for example, development of a latent image or the like formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.

Toner for electrostatic image development

A toner for electrostatic image development, containing a resin binder containing a polyester having monomer units wherein at least one monomer is selected from the group consisting of fumaric acid and maleic acid, including mixtures thereof; a colorant; and a charge control agent containing a negatively chargeable charge control agent and a positively chargeable charge control agent, wherein the unreacted monomers of fumaric acid, maleic acid or both fumaric acid and maleic acid are contained in the toner in an amount of 0.20% by weight or less. The toner for electrostatic image development of the present invention may be used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

A toner comprising a resin binder, a colorant, and fine inorganic particles having a BET specific surface area of 30 m/g or less, wherein the fine inorganic particles are added as an external additive, wherein the toner has a storage modulus at 100&#xb0; C. using a 25 mm parallel plate of 7&#xd7;10Pa or less, a storage modulus at 60&#xb0; C. using a 7.9 mm parallel plate of from 3&#xd7;10to 1&#xd7;10Pa, and a storage modulus at 70&#xb0; C. using a 7.9 mm parallel plate of from 7&#xd7;10to 3&#xd7;10Pa; and a two-component developer comprising the toner. The toner can be used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

Toner

A toner comprising a resin binder, a colorant, and externally-added inorganic fine particles, comprising large-particle size inorganic particles comprising 50% by volume or more of particles having a particle size of from 100 to 583.9 nm, and having a BET specific surface area of 1 to 40 m/g. The toner can be used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

A two-component developer comprising a toner onto which a hydrophobic silica having an average particle size of 25 nm or more is externally added, and a carrier having a saturation magnetization of from 50 to 95 Am /kg, wherein the carrier has a ratio of surface resistivity to volume resistivity of from 1&times;10 to 1&times;10 m at an electric field strength of 100 V/cm; and a method for development comprising applying the above two-component developer to an electrophotographic device comprising a photoconductor having a peripheral speed of 400 mm/sec or more, and developing a latent image. The two-component developer can be used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.

Two-component developer

A developing method of the present invention has the steps of forming a uniform layer of a nonmagnetic one-component toner on a developer carrying sleeve with a developer blade; rotating an electrostatic latent image forming member and the developer carrying sleeve; and applying the toner on the developer carrying sleeve onto an electrostatic latent image formed on the electrostatic latent image forming member. The toner used herein is an encapsulated toner having a heat-fusible core material and a shell formed thereon. By using this development for a nonmagnetic one-component toner of the present invention, clear images free from background can be stably formed for a large number of copying.

Method of development of nonmagnetic one-component toner and method for

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:

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Wakayama, Japan

Koji Kameyama