Patents by Inventor Takashi Hayakawa

Takashi Hayakawa 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: 5085968
    Abstract: A photosensitive member for electrophotography which comprises a conductive substrate and a photoconductive layer which is composed of an amorphous silicon layer and an amorphous silicon germanium layer containing a specific amount of hydrogen and/or halogen respectively, and being prepared by electron cyclotron resonance method respectively, which is useful for xerographic systems.
    Type: Grant
    Filed: December 3, 1990
    Date of Patent: February 4, 1992
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Hayakawa, Shiro Narikawa, Kunio Ohashi
  • Patent number: 5057391
    Abstract: A photosensitive member for electrophotography comprising a photoconductive layer formed on an electro- conductive support, in which the photoconductive layer is composed of an amorphous silicon germanium layer formed by electron cyclotron resonance (ECR) method and containing hydrogen and/or halogen in an amount of more than 40 at. % to 65 at. % and an amorphous silicon nitride layer formed by ECR method and containing hydrogen and/or halogen in an amount of more than 40 at. % to 60 at. %, the amorphous silicon nitride layer being laminated on the amorphous silicon germanium layer; said member exhibiting an increased sensitivity to laser rays having a long wavelength and an improved charge retention capacity.
    Type: Grant
    Filed: May 15, 1990
    Date of Patent: October 15, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Hayakawa, Shiro Narikawa, Kunio Ohashi, Yoshiharu Tsujimoto
  • Patent number: 5009977
    Abstract: A photosensitive member for electrophotographic photoreceptor, composed of an amorphous silicon containing carbon; nitrogen or oxygen and a specific amount of hydrogen and/or halogen, prepared by electron cyclotron resonance method, which is useful for xerographic systems.
    Type: Grant
    Filed: June 21, 1989
    Date of Patent: April 23, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Hayakawa, Shiro Narikawa, Kunio Ohashi, Yoshiharu Tsujimoto
  • Patent number: 4994855
    Abstract: A photoreceptor for an image formation apparatus has a photosensitive layer of a multi-layer structure each having the characteristic of increasing its electrical resistance at a different rate upon expose to light. An image-carrying beam of reflected light from an original to be copied is made incident on the photoreceptor to form a resistance image. An electrostatic latent image is formed therefrom either on the photoreceptor itself or on a transfer medium placed in contact therewith and a visible toner image is formed by applying toner on such an electrostatic image but the resistance image on the photoreceptor remains undisturbed during such image transfer processes. Thus, a plurality of copies of a single original can be produced without exposing the photoreceptor to reflected light therefrom for each copy to be printed.
    Type: Grant
    Filed: May 26, 1988
    Date of Patent: February 19, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Kunio Ohashi, Yoshikazy Fujiwara, Shiro Narikawa, Shoichi Nagata, Kazuki Wakita, Takashi Hayakawa
  • Patent number: 4992348
    Abstract: A photosensitive member for electrophotography which comprises a conductive substrate and a photoconductive layer which is composed of an amorphous silicon layer and an amorphous silicon germanium layer containing a specific amount of hydrogen and/or halogen respectively, and being prepared by electron cyclotron resonance method respectively, which is useful for xerographic systems.
    Type: Grant
    Filed: June 27, 1989
    Date of Patent: February 12, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Hayakawa, Shiro Narikawa, Kunio Ohashi
  • Patent number: 4990423
    Abstract: A photosensitive member for electrophotography which comprises a conductive substrate and a photoconductive layer, the photoconductive layer being an amorphous silicon germanium containing hydrogen and/or a halogen at a specific amount, deposited by electron cyclotron resonance method, which is useful for image formation apparatus such as a laser printer.
    Type: Grant
    Filed: June 20, 1989
    Date of Patent: February 5, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Hayakawa, Shiro Narikawa, Kunio Ohashi
  • Patent number: 4971878
    Abstract: An electrophotographic photosensitive member is disclosed which comprises an electrically conductive substrate and a photoconductive layer formed on said substrate, wherein the photoconductive layer is made of amorphous silicon containing 40 atomic % or more of hydrogen and/or halogen.
    Type: Grant
    Filed: April 3, 1989
    Date of Patent: November 20, 1990
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Hayakawa, Shiro Narikawa, Kunio Ohashi
  • Patent number: 4952712
    Abstract: 2,3-Dimethoxy-5-methylbenzoquinone is prepared by oxidizing 3,4,5-trimethoxytoluene by reaction with hydrogen peroxide in the presence of a catalyst which is a heteropolyacid selected from phosphomolybdic acids, phosphotungstic acids, silicomolybdic acids and silicotungstic acids or a salt thereof.
    Type: Grant
    Filed: March 13, 1989
    Date of Patent: August 28, 1990
    Assignee: Director-General of Agency of Industrial Science and Technology
    Inventors: Hideo Orita, Masao Shimizu, Takashi Hayakawa, Katsuomi Takehira
  • Patent number: 4943503
    Abstract: An amorphous silicon (a-Si) photoreceptor includes an amorphous silicon (a-Si) photoconductive layer, and a surface layer disposed above the amorphous silicon (a-Si) photoconductive layer. An intermediate layer is disposed between the amorphous-silicon (a-Si) photoconductive layer and the surface layer to ensure the energy level matching. The intermediate layer is made of amorphous silicon (a-Si) doped with nitrogen and boron so as to have the energy difference of less than 0.2 eV between the bottom of the conduction bands of the surface layer and the intermediate layer.
    Type: Grant
    Filed: October 10, 1984
    Date of Patent: July 24, 1990
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hideo Nojima, Yoshimi Kojima, Eiji Imada, Toshiro Matsuyama, Takashi Hayakawa, Shiro Narikawa, Shaw Ehara
  • Patent number: 4853309
    Abstract: A photoreceptor for electrophotography including an electrically conductive substrate, a bottom layer, a photoconductive layer composed mainly of amorphous silicon, and a surface layer, in that order. Both the bottom and surface layers have a greater optical bandgap than said photoconductive layer. A first middle layer is disposed between said bottom layer and said photoconductive layer, and a second middle layer is disposed between said photoconductive layer and said surface layer. Both the first and second middle layers are composed mainly of amorphous silicon and have a concentration of doped atoms which varies from the bottom to the top of the layer.
    Type: Grant
    Filed: June 3, 1988
    Date of Patent: August 1, 1989
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takashi Hayakawa, Hideo Nojima, Yoshimi Kojima, Shiro Narikawa, Toshiro Matsuyama, Eiji Imada, Shaw Ehara
  • Patent number: 4687724
    Abstract: A photoreceptor for electrophotography utilizing a-Si:N:H:F, wherein a stable high-sensitive layer is provided and the time-lapse variation in characteristics is reduced in the use of an a-Si.sub.1-x N.sub.x layer as a sensitive layer.
    Type: Grant
    Filed: December 14, 1983
    Date of Patent: August 18, 1987
    Assignee: Sharp Kabushiki
    Inventors: Shaw Ehara, Yoshimi Kojima, Eiji Imada, Takashi Hayakawa, Toshiro Matsuyama
  • Patent number: 4666816
    Abstract: A method of manufacturing an electrophotographic photoreceptor having an amorphous silicon layer formed as a photoconductive layer, on an electrically conductive support member. The manufacturing method includes the steps of preparing the amorphous silicon layer as the photoconductive layer by employing Si.sub.2 H.sub.6 (disilane) as a main raw material gas through a glow discharge process, and simultaneously, adding nitrogen and boron to the main raw material gas, with the unsaturated bond being stabilized by hydrogen or hydrogen and fluorine.
    Type: Grant
    Filed: August 26, 1986
    Date of Patent: May 19, 1987
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshimi Kojima, Shiro Narikawa, Takashi Hayakawa, Hideo Nojima, Eiji Imada, Toshiro Matsuyama, Shaw Ehara
  • Patent number: 4615299
    Abstract: A plasma CVD (chemical vapor deposition) apparatus of the capacitance coupling type for effecting the chemical vapor deposition on a drum which includes an air tight chamber made of an electrically conductive material, a support provided in the chamber for supporting the drum inside the chamber in an electrically insulated relationship with the chamber, and an RF power source for supplying RF power to the drum. The chamber is grounded and, therefore, the plasma is generated between the drum and inside wall of the chamber. The apparatus is provided with means for providing a smooth surface on the drum. The drum can be used as a photoreceptor for use in an electrophotographic copying machine.
    Type: Grant
    Filed: March 7, 1985
    Date of Patent: October 7, 1986
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Toshiro Matsuyama, Takashi Hayakawa, Yoshimi Kojima, Shiro Narikawa, Shaw Ehara
  • Patent number: 4400544
    Abstract: The invention provides an efficient method for the preparation of cycloheone by the liquid-phase oxidation of cyclohexene in the presence of a catalyst system. The rate of conversion of the cyclohexene and the yield of cyclohexanone are unexpectedly increased when the reaction mixture brought into contact with oxygen or air contains a limited amount of an aliphatic alcohol having 2-10 carbon atoms in a molecule such as ethyl alcohol with the catalyst system composed of a palladium compound, e.g. PdCl.sub.2, and at least one co-catalytic ingredient which is a copper compound or iron compound such as CuCl.sub.2 or FeCl.sub.3. The influence of benzene or cyclohexane admixed in the reaction mixture was studied to indicate no adverse effects or even better results in the reaction giving further advantages of the process in which the starting cyclohexene need not be purified and can be used as prepared by the partial hydrogenation of benzene or partial dehydrogenation of cyclohexane.
    Type: Grant
    Filed: January 22, 1982
    Date of Patent: August 23, 1983
    Assignee: Director-General of the Agency of Industrial Science and Technology
    Inventors: Katsuomi Takehira, Toshio Ishikawa, Takashi Hayakawa, Juichi Imamura
  • Patent number: 3969428
    Abstract: A process for the production of conjugated diolefins having 4-6 carbon atoms from the corresponding monoolefins according to the oxidative dehydrogenation process wherein oxides of molybdenum, arsenic and an alkaline earth metal are used as catalyst. The use of this catalyst enables the production of conjugated diolefins in a high yield.
    Type: Grant
    Filed: October 11, 1974
    Date of Patent: July 13, 1976
    Assignee: Agency of Industrial Science & Technology
    Inventors: Toshio Ishikawa, Takashi Hayakawa, Tsutomu Nishimura, Michio Araki, Katsuomi Takehira