Patents by Inventor Hirofumi Yamanami

Hirofumi Yamanami 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: 9063441
    Abstract: Provided is an electrophotographic photoconductor including an electroconductive substrate, a photoconductive layer on the electroconductive substrate, and a protection layer on the photoconductive layer, wherein the protection layer contains two or more metal oxides having different average primary particle diameters, a binder resin, and a charge transporting material, the content of the metal oxides in the protection layer is 50% by mass or higher, and the average primary particle diameters of the metal oxides satisfy all of formula (I) to (III) below: d(1)<d(2)??formula (I); d(1)/d(2)?0.25??formula (II); and 0.1 ?m?d(2)??formula (III) where d(1) represents the average primary particle diameter (?m) of one metal oxide of the two or more metal oxides contained in the protection layer, and d(2) represents the average primary particle diameter (?m) of another or the other metal oxide of the two or more metal oxides contained in the protection layer.
    Type: Grant
    Filed: October 22, 2013
    Date of Patent: June 23, 2015
    Assignee: Ricoh Company, Ltd.
    Inventors: Hirofumi Yamanami, Koji Enomoto, Naoyuki Esaki
  • Publication number: 20140120463
    Abstract: Provided is an electrophotographic photoconductor including an electroconductive substrate, a photoconductive layer on the electroconductive substrate, and a protection layer on the photoconductive layer, wherein the protection layer contains two or more metal oxides having different average primary particle diameters, a binder resin, and a charge transporting material, the content of the metal oxides in the protection layer is 50% by mass or higher, and the average primary particle diameters of the metal oxides satisfy all of formulae (I) to (III) below: d(1)<d(2)??formula (I); d(1)/d(2)?0.25??formula (II); and 0.1 ?m?d(2)??formula (III) where d(1) represents the average primary particle diameter (?m) of one metal oxide of the two or more metal oxides contained in the protection layer, and d(2) represents the average primary particle diameter (?m) of another or the other metal oxide of the two or more metal oxides contained in the protection layer.
    Type: Application
    Filed: October 22, 2013
    Publication date: May 1, 2014
    Inventors: Hirofumi YAMANAMI, Koji ENOMOTO, Naoyuki ESAKI
  • Patent number: 7348115
    Abstract: An electrophotographic photoconductor, including an electrically conductive substrate, an undercoat layer containing a filler and a binder resin and provided on the substrate, and a photoconductive layer provided on the undercoat layer and containing a binder resin. At least one compound selected from crown ethers, polyalkyleneglycol ethers, polyethyleneglycol monocarboxylic acid esters, polyethyleneglycol dicarboxylic acid esters, and hydroxy-terminated random or block copolymers containing oxypropylene and oxyethylene groups is incorporated into (a) the undercoat layer or (b) into a charge generating layer of the photoconductive layer. In the case of (a), the photoconductive layer is a dried coating of a composition containing at least one solvent selected from cyclic ethers, ketones and aromatic hydrocarbons.
    Type: Grant
    Filed: March 29, 2005
    Date of Patent: March 25, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Hirofumi Yamanami, Yukari Yamada
  • Patent number: 7267914
    Abstract: An electrophotographic photoconductor, including an electrically conductive substrate, an undercoat layer containing a filler and a binder resin and provided on the substrate, and a photoconductive layer provided on the undercoat layer and containing a binder resin. At least one compound selected from crown ethers, polyalkyleneglycol ethers, polyethyleneglycol monocarboxylic acid esters, polyethyleneglycol dicarboxylic acid esters, and hydroxy-terminated random or block copolymers containing oxypropylene and oxyethylene groups is incorporated into (a) the undercoat layer or (b) into a charge generating layer of the photoconductive layer. In the case of (a), the photoconductive layer is a dried coating of a composition containing at least one solvent selected from cyclic ethers, ketones and aromatic hydrocarbons.
    Type: Grant
    Filed: December 6, 2002
    Date of Patent: September 11, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Hirofumi Yamanami, Yukari Yamada
  • Publication number: 20050170271
    Abstract: An electrophotographic photoconductor, including an electrically conductive substrate, an undercoat layer containing a filler and a binder resin and provided on the substrate, and a photoconductive layer provided on the undercoat layer and containing a binder resin. At least one compound selected from crown ethers, polyalkyleneglycol ethers, polyethyleneglycol monocarboxylic acid esters, polyethyleneglycol dicarboxylic acid esters, and hydroxy-terminated random or block copolymers containing oxypropylene and oxyethylene groups is incorporated into (a) the undercoat layer or (b) into a charge generating layer of the photoconductive layer. In the case of (a), the photoconductive layer is a dried coating of a composition containing at least one solvent selected from cyclic ethers, ketones and aromatic hydrocarbons.
    Type: Application
    Filed: March 29, 2005
    Publication date: August 4, 2005
    Inventors: Hirofumi Yamanami, Yukari Yamada
  • Publication number: 20030232265
    Abstract: An electrophotographic photoconductor, including an electrically conductive substrate, an undercoat layer containing a filler and a binder resin and provided on the substrate, and a photoconductive layer provided on the undercoat layer and containing a binder resin. At least one compound selected from crown ethers, polyalkyleneglycol ethers, polyethyleneglycol monocarboxylic acid esters, polyethyleneglycol dicarboxylic acid esters, and hydroxy-terminated random or block copolymers containing oxypropylene and oxyethylene groups is incorporated into (a) the undercoat layer or (b) into a charge generating layer of the photoconductive layer. In the case of (a), the photoconductive layer is a dried coating of a composition containing at least one solvent selected from cyclic ethers, ketones and aromatic hydrocarbons.
    Type: Application
    Filed: December 6, 2002
    Publication date: December 18, 2003
    Inventors: Hirofumi Yamanami, Yukari Yamada
  • Patent number: 6355390
    Abstract: An electrophotographic photoconductor has an electroconductive support, and an undercoat layer and a photoconductive layer which are successively overlaid on the support, the undercoat layer containing an inorganic pigment and a crosslinked N-alkoxymethylated polyamide or a crosslinked material of an N-alkoxymethylated polyamide and a melamine resin as a binder resin. The method of producing the photoconductor is also disclosed. An electrophotographic image forming apparatus is provided with the aforementioned photoconductor, a charging unit, and a developing unit. A process cartridge is provided with the photoconductor, and at least one of a charging unit, a light exposure unit, a developing unit, or an image transfer unit. An electrophotographic image forming process has the steps of forming a latent electrostatic image on the photoconductor, and developing the latent electrostatic image to a visible image by reversal development.
    Type: Grant
    Filed: August 4, 2000
    Date of Patent: March 12, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Hirofumi Yamanami, Tamotsu Aruga
  • Patent number: 4871635
    Abstract: A repeatedly usable electrophotographic photoconductor comprising (a) an electroconductive support, (b) an undercoat layer containing therein at least one salt selected from the group consisting of carboxylates, amino carboxylates, phosphates, polyphosphates, phosphites, phosphate derivatives, borates, sulfates and sulfites, and (c) a photoconductive layer, which layers are successively overlaid on the electroconductive support.
    Type: Grant
    Filed: May 13, 1988
    Date of Patent: October 3, 1989
    Assignee: Ricoh Company, Ltd.
    Inventors: Kenji Seki, Junichiroh Hashimoto, Michio Kimura, Hirofumi Yamanami, Satomi Mochizuki, Izumi Aiso
  • Patent number: 4775605
    Abstract: This invention relates to a repeatedly usable photosensitive material for electrophotography, comprising an electroconductive substrate, a photosensitive layer and an intermediate layer located between said electroconductive substrate and said photosensitive layer, characterized in that said intermediate layer comprises an electroconductive polymer and an inorganic white pigment.
    Type: Grant
    Filed: December 31, 1986
    Date of Patent: October 4, 1988
    Assignee: Ricoh Co., Ltd.
    Inventors: Kenji Seki, Katsuichi Ohta, Kiyoshi Masuda, Hirofumi Yamanami, Satomi Mochizuki