Patents by Inventor Eiichi Takasuna

Eiichi Takasuna 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: 4844963
    Abstract: Fillers are mixed into a resin solution used to form a resin layer on the substrate of a magnetic disk. Therefore, the distance from the boundary between the resin layer and magnetic film to the filler top as well as the distance from the surface of the magnetic film to the top of the filler in the magnetic film are freely adjustable by appropriately setting the particle size of mixed fillers, thickness of the resin layer and thickness of magnetic film independently or in combination. Thus, the magnetic disk can be designed with a considerably improved freedom.
    Type: Grant
    Filed: February 1, 1988
    Date of Patent: July 4, 1989
    Assignee: 501 Hitachi, Ltd.
    Inventors: Eiichi Takasuna, Masaaki Imamura
  • Patent number: 4721646
    Abstract: A magnetic recording medium of the present invention comprises: a substrate; a magnetic film formed on this substrate; and a nonmagnetic reinforcing agent mixed into the magnetic film and projected from the surface of the magnetic film. Assuming that the minimum flying height of the magnetic head which is lifted up over the magnetic film is h, a projection height T of the nonmagnetic reinforcing agent from the surface of the magnetic film satisfies the relation of h/4<T<h. By virtue of this, even if an amount of mixture of the nonmagnetic reinforcing agent which becomes a cause of the generation of the noises is reduced, the necessary durability can be obtained.
    Type: Grant
    Filed: August 28, 1986
    Date of Patent: January 26, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Keigo Iechika, Fuzio Maeda, Masa-aki Imamura, Yoshiki Kato, Eiichi Takasuna, Youichi Kawakubo