Patents by Inventor Tomohito Nakajima

Tomohito Nakajima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20030194628
    Abstract: A magenta toner for electrophotography includes a binder resin and a colorant, wherein the toner contains at least a naphthol pigment having a structure represented by the following general formula (1) as the colorant, and has a shape factor SF1 of 110 to 140 obtained by the equation below and a volume average particle size of 2 to 9 &mgr;m: 1
    Type: Application
    Filed: August 16, 2002
    Publication date: October 16, 2003
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Satoshi Yoshida, Yasuo Matsumura, Toyofumi Inoue, Hidekazu Yaguchi, Takahisa Fujii, Tomohito Nakajima
  • Publication number: 20030180641
    Abstract: A toner for developing an electrostatic latent image is provided that can prevent occurrence of blister even with coated paper having a coated surface, exhibits excellent releasing performance in oilless fixing, and realizes both high glossiness and OHP transparency for an image to be formed. A process for producing the toner, a developer containing the toner, and a process for forming an image using the toner are also provided. The toner for developing an electrostatic latent image contains a binder resin, a releasing agent and a colorant, in which the binder resin has a number average molecular weight (Mn) in a range of from 9,000 to 18,000 and a molecular weight distribution represented by a ratio (Mw/Mn) of a weight average molecular weight (Mw) and a number average molecular weight (Mn) of 2.5 or less, and the binder resin contains a vinyl resin.
    Type: Application
    Filed: August 16, 2002
    Publication date: September 25, 2003
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Tomohito Nakajima, Satoshi Yoshida, Hidekazu Yaguchi, Takahisa Fujii, Yasuo Matsumura
  • Publication number: 20030175611
    Abstract: The present invention relates to a method of forming images. The method includes the steps of forming electrostatic latent images on an electrostatic image carrier, forming toner images with a toner-containing developer by developing the electrostatic latent images on the electrostatic image carrier, transferring the toner images onto a transfer material, and thermally fixing the toner images, wherein an electrophotographic toner including containing at least a binder resin, a colorant, and a releasing agent in the range of 10 to 25% by mass relative to toner particles and having a shape factor SF1 of 140 or less is used as the toner, and the thermal fixing step is carried out so as to satisfy, at a process speed of at least 170 mm/sec., the relationship (A): 200<0.7×&agr;+2000×&bgr; wherein &agr; is a fixing temperature (° C.), &bgr; is a heating time (second), and &agr; is 160° C. or higher.
    Type: Application
    Filed: January 15, 2003
    Publication date: September 18, 2003
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Takahisa Fujii, Yasuo Matsumura, Hidekazu Yaguchi, Satoshi Yoshida, Tomohito Nakajima
  • Publication number: 20030148202
    Abstract: Such a toner for developing an electrostatic image is to be provided that has a wide fixable temperature range, is excellent in development and transfer performance and excellent in releasing performance, realizes both glossiness and transparency, and is capable of providing an image (particularly a color image) of a wide color reproduction range having high quality and high durability, a developer for an electrostatic image, and a process for forming an image. The toner for developing an electrostatic image contains a binder resin, a colorant and an inorganic metallic salt, and an amount of a toluene insoluble component (provided that the colorant, a releasing agent and inorganic and organic insoluble particles are excluded therefrom) is from 0.5 to 10% by weight. The developer for an electrostatic image and the process for forming an image use the toner for developing an electrostatic image.
    Type: Application
    Filed: August 16, 2002
    Publication date: August 7, 2003
    Applicant: FUJI XEROX CO., LTD.
    Inventors: Yasuo Matsumura, Hidekazu Yaguchi, Satoshi Yoshida, Takahisa Fujii, Tomohito Nakajima
  • Patent number: 6489075
    Abstract: A toner for developing an electrostatic latent image, a process for producing the same, and a developer for developing an electrostatic latent image using the same are provided, in which the toner flowability, the charging property, the developing property, the transferring property and the fixing property are simultaneously satisfied in a long period of time. The toner for developing an electrostatic latent image comprising a colored particles containing a binder resin, a coloring agent and a releasing agent, and an external additive, the external additive containing a monodisperse spherical inorganic oxide having a true specific gravity of from 1.3 to 1.9 and a volume average particle diameter of from 80 to 300 nm. It is preferred that the inorganic oxide is silica, the colored particles have a shape coefficient of 125 or less, and the external additive further contains a reaction product of metatitanic acid and a coupling agent, which has an electric resistance of 1010 &OHgr;.cm or more.
    Type: Grant
    Filed: February 1, 2002
    Date of Patent: December 3, 2002
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Chiaki Suzuki, Masahiro Takagi, Satoshi Inoue, Yosuke Tsurumi, Kozo Ota, Sakon Takahashi, Tomohito Nakajima, Atsuhiko Eguchi
  • Patent number: 6479206
    Abstract: A toner for developing an electrostatic latent image, a process for producing the same, and a developer for developing an electrostatic latent image using the same are provided, in which the toner flowability, the charging property, the developing property, the transferring property and the fixing property are simultaneously satisfied in a long period of time. The toner for developing an electrostatic latent image comprising a colored particles containing a binder resin, a coloring agent and a releasing agent, and an external additive, the external additive containing a monodisperse spherical inorganic oxide having a true specific gravity of from 1.3 to 1.9 and a volume average particle diameter of from 80 to 300 nm. It is preferred that the inorganic oxide is silica, the colored particles have a shape coefficient of 125 or less, and the external additive further contains a reaction product of metatitanic acid and a coupling agent, which has an electric resistance of 1010 &OHgr;·cm or more.
    Type: Grant
    Filed: April 26, 2002
    Date of Patent: November 12, 2002
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Chiaki Suzuki, Masahiro Takagi, Satoshi Inoue, Yosuke Tsurumi, Kozo Ota, Sakon Takahashi, Tomohito Nakajima, Atsuhiko Eguchi
  • Publication number: 20020160293
    Abstract: A carrier for the development of an electrostatic latent image, comprising a core material and a resin coating the core material therewith, wherein the coating resin comprises a copolymer of at least four kinds of monomers including: (1) a monomer containing a carboxyl group; (2) an acrylic acid alkylester monomer or methacrylic acid alkylester monomer, containing a C1-C3 linear alkyl group; (3) an acrylic acid alkylester monomer or methacrylic acid alkylester monomer, containing a C4-C10 linear alkyl group or C3-C10 branched alkyl group; and (4) a monomer containing fluorine. Also disclosed is a two-component developer for the development of an electrostatic latent image, comprising a toner and the carrier.
    Type: Application
    Filed: October 16, 2001
    Publication date: October 31, 2002
    Applicant: FUJI XEROX CO., LTD
    Inventors: Sakon Takahashi, Hiroshi Nakazawa, Tomohito Nakajima, Masahiro Takagi, Atsuhiko Eguchi
  • Patent number: 6447972
    Abstract: A charge-providing member or carrier for the development of an electrostatic latent image comprising a resin coat layer provided on a core material, characterized in that the coating resin comprises a (meth)acrylic acid alkyl ester copolymer containing as copolymerizing components a (meth) acrylic acid alkyl ester containing a branched alkyl group having 4 or more carbon atoms and a (meth) acrylic acid alkyl ester containing a fluorine-containing alkyl group, a developer comprising such a carrier, and a sleeve for carrying such a developer.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: September 10, 2002
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Tomohito Nakajima, Sakon Takahashi, Kozo Ota, Chiaki Suzuki
  • Publication number: 20020115008
    Abstract: A toner for developing an electrostatic latent image, a process for producing the same, and a developer for developing an electrostatic latent image using the same are provided, in which the toner flowability, the charging property, the developing property, the transferring property and the fixing property are simultaneously satisfied in a long period of time. The toner for developing an electrostatic latent image comprising a colored particles containing a binder resin, a coloring agent and a releasing agent, and an external additive, the external additive containing a monodisperse spherical inorganic oxide having a true specific gravity of from 1.3 to 1.9 and a volume average particle diameter of from 80 to 300 nm. It is preferred that the inorganic oxide is silica, the colored particles have a shape coefficient of 125 or less, and the external additive further contains a reaction product of metatitanic acid and a coupling agent, which has an electric resistance of 1010 &OHgr;cm or more.
    Type: Application
    Filed: February 1, 2002
    Publication date: August 22, 2002
    Applicant: Fuji Xerox Co., Ltd.
    Inventors: Chiaki Suzuki, Masahiro Takagi, Satoshi Inoue, Yosuke Tsurumi, Kozo Ota, Sakon Takahashi, Tomohito Nakajima, Atsuhiko Eguchi
  • Patent number: 6403271
    Abstract: A toner for developing an electrostatic latent image, a process for producing the same, and a developer for developing an electrostatic latent image using the same are provided, in which the toner flowability, the charging property, the developing property, the transferring property and the fixing property are simultaneously satisfied in a long period of time. The toner for developing an electrostatic latent image comprising a colored particles containing a binder resin, a coloring agent and a releasing agent, and an external additive, the external additive containing a monodisperse spherical inorganic oxide having a true specific gravity of from 1.3 to 1.9 and a volume average particle diameter of from 80 to 300 nm. It is preferred that the inorganic oxide is silica, the colored particles have a shape coefficient of 125 or less, and the external additive further contains a reaction product of metatitanic acid and a coupling agent, which has an electric resistance of 1010 &OHgr;·cm or more.
    Type: Grant
    Filed: June 1, 2000
    Date of Patent: June 11, 2002
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Chiaki Suzuki, Masahiro Takagi, Satoshi Inoue, Yosuke Tsurumi, Kozo Ota, Sakon Takahashi, Tomohito Nakajima, Atsuhiko Eguchi
  • Patent number: 6242146
    Abstract: A carrier for two-component electrostatic-charged image developer, at least the surface of which is coated with a resin, is provided. The apparent density &rgr; (g/cm3) of the carrier, the mean particle diameter D (cm) of the carrier, and the specific area S (cm2/g) of the carrier core material satisfy the following conditions: 600≦S≦1500 10/(D×&rgr;)−S≦300. A two-component developer and an image-forming process using the carrier are also provided.
    Type: Grant
    Filed: February 7, 2000
    Date of Patent: June 5, 2001
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Yuka Ishihara, Hiroshi Nakazawa, Akihiro Iizuka, Yoshifumi Iida, Kaori Oishi, Tomohito Nakajima, Takashi Imai, Masanori Ichimura