Patents by Inventor Sakon Takahashi

Sakon Takahashi 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).

  • 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: 6040102
    Abstract: An electrostatic latent image developer including a toner, which is formed from an outer additive and non-magnetic resin particles containing a binder resin and a coloring agent, and a carrier, in which a resin coating layer in which electroconductive fine powder is dispersed in a matrix resin is formed on a core, wherein a volume specific resistivity of said carrier is greater than or equal to 10.sup.9 .OMEGA..multidot.cm at an electric field strength of 3000 V/cm and is less than or equal to 10.sup.13 .OMEGA..multidot.cm at an electric field strength of 10000 V/cm, said outer additive contains titanium oxide whose volume specific resistivity of a compression-molded molded product is greater than or equal to 10.sup.6 .OMEGA..multidot.cm at an electric field strength of 3000 V/cm and is less than or equal to 10.sup.10 .OMEGA..multidot.
    Type: Grant
    Filed: December 1, 1997
    Date of Patent: March 21, 2000
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Sakon Takahashi, Shinpei Takagi, Noriyuki Mizutani, Yasuhiro Oya, Haruhide Ishida
  • Patent number: 5849448
    Abstract: The present invention provides a carrier for developer of an electrostatic latent image and related technologies. The carrier is excellent in the ability to impart charge suitably and stably to toner and has a structure durable enough to maintain the ability for a long period of time such that the structure can prevent the toner from being adhered onto the carrier surface for a long period of time.The carrier comprises a core covered with a resin coating layer containing resin particles and an electroconductive fine powder in the form of a dispersion in a matrix resin.The carrier can be produced by a method comprising the steps of preparing a coating solution by placing materials in a solvent which can dissolve the matrix resin, but cannot dissolve the resin particles, dispersing the particles of the resin, applying the solution to a core and removing the solvent. A high-quality image can be formed by use of the developer comprising the carrier and the toner.
    Type: Grant
    Filed: March 17, 1997
    Date of Patent: December 15, 1998
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Susumu Yoshino, Satoshi Inoue, Kaori Ohishi, Shinpei Takagi, Sakon Takahashi, Noriyuki Mizutani
  • Patent number: 5629120
    Abstract: The present invention provides an electrostatic image developing carrier which exhibits an enhanced maintenance of image quality, can be prevented from being attached to the image and thus can provide an image free of uneven density and background stain and an electrostatic image developer comprising said carrier. A novel electrostatic image developing carrier comprising a ferrite is provided, characterized in that said ferrite has a copper content of from 0.1 ppm to 2,500 ppm, a zinc content of from 0.1 ppm to 5,000 ppm and a nickel content of from 0.1 ppm to 2,000 ppm.
    Type: Grant
    Filed: October 16, 1995
    Date of Patent: May 13, 1997
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Manabu Serizawa, Ikutaroh Nagatsuka, Haruhide Ishida, Sakon Takahashi