Patents by Inventor Sakae Ohta

Sakae Ohta 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).

  • Magnetic recording medium having a lubricant film consisting of a mixture of two lubricants and which has two peaks of molecular weight
    Patent number: 5162163
    Abstract: This invention relates to a magnetic recording medium wherein the improvement comprises a lubricative film comprising a lubricant having a functional group at one end of the molecule and a lubricant having a functional group at both ends of the molecule. According to the present invention, there are provided a magnetic recording medium having excellent sliding tolerance against the head, reduced adhesiveness and dense surface, and a magnetic storage device using such a recording medium.
    Type: Grant
    Filed: September 11, 1990
    Date of Patent: November 10, 1992
    Assignee: Hitachi Ltd.
    Inventors: Sakae Ohta, Hiroyuki Matsumoto, Miyuki Kajiki, Makoto Komatsu, Kenzo Masuda, Fumio Nakano
  • Magnetic recording media for longitudinal recording
    Patent number: 4792497
    Abstract: Disclosed is a magnetic recording medium of the magnetic metal thin-film type for longitudinal recording, in which the noise is reduced by selecting the value of maximum torque L (the product of magnetic anisotropy energy Ku and magnetic layer volume v; as measured by setting the axis of rotation in plane of the medium) and the value of magnetic flux .phi. (the product of saturation magnetization Ms and magnetic layer volume v) from a range defined by 0<L/(2.pi..multidot..phi..sup.2)<4.times.10.sup.5 (erg/emu.sup.2).
    Type: Grant
    Filed: January 28, 1988
    Date of Patent: December 20, 1988
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Suzuki, Yoshihiro Shiroishi, Sadao Hishiyama, Tomoyuki Ohno, Kazuetsu Yoshida, Shyuichi Kojima, Susumu Funamoto, Yasushi Kitazaki, Sakae Ohta, Hajime Aoi
  • Powder material transportation apparatus
    Patent number: 4297021
    Abstract: The powder material transportation apparatus for transporting powder materials such as developer powder, by a rotating member such as a coil is provided with an agitator for destroying a bridge of powder material which is apt to be formed in an upper portion of the rotating member. The diameter or pitch of a rotating coil member is designed to be greater in a transportation termination portion than in a transportation initiation portion, whereby the powder material transportation force is increased in the transportation termination portion and formation of the bridge of powder material is prevented.
    Type: Grant
    Filed: June 6, 1979
    Date of Patent: October 27, 1981
    Assignee: Ricoh Company, Ltd.
    Inventors: Tatsuo Tani, Yasumori Nagahara, Sakae Ohta, Minoru Suzuki, Kiyozo Hashizume
  • Means for driving a movable body
    Patent number: 4281557
    Abstract: A mechanism for driving a movable body including a movable body reciprocatingly movable along guide members, a member for driving said movable body reciprocatingly, a wire for connecting the movable body with the driving member, a tension member arranged in a slack portion of the wire during the time of advancing movement of the movable body and elastic means for providing a strong or a weak tension force to the tension member, the weak tension force being applied to the tension member during advancing movement of the movable body and the strong tension force being applied to the tension member during returning movement of the movable body.
    Type: Grant
    Filed: July 16, 1979
    Date of Patent: August 4, 1981
    Assignee: Kabushiki Kaisha Ricoh
    Inventors: Sakae Ohta, Tatsuo Tani