Patents by Inventor Hiroshi Tomishima

Hiroshi Tomishima 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: 5910863
    Abstract: A magnetic disk recording device having a continuous medium type magnetic disk and a magnetic head slider, wherein the magnetic head slider is formed of a sintered body essentially consisting of titanium oxide as the major component thereof and at least one selected from the group consisting of Y, Yb, Nb, Mg, Er, Fe, Cr, Zr and Al in an amount of from 2 atm % to 50 atm % with respect to the titanium oxide, whereby a higher recording density is realized while maintaining a higher reliability of the device over long time span.
    Type: Grant
    Filed: October 30, 1996
    Date of Patent: June 8, 1999
    Assignees: Hitachi, Ltd., Hitachi Metals, Ltd.
    Inventors: Takeshi Miyazaki, Yasutaka Suzuki, Hiroshi Tomishima
  • Patent number: 5290738
    Abstract: A nonmagnetic oxide substrate material has a composition of 15 to 60 mol % of NiO, 10 to 70 mol % of CoO, 10 to 40 mol % of TiO.sub.2, and 0.5 to 25 mol % of CaO and is formed of very minute crystal grains. Preferably MgO or ZrO.sub.2 is used as an additive to the material to present a total composition containing the additive of 0.5 to 3 wt % per 100 parts by weight of the nonmagnetic oxide substrate material. Preferably, the substrate material is formulated to have a thermal expansion coefficient falling in the range of from 100 to 140 X 10.sup.-7 /.degree.C. A magnetic head using this substrate material reduces the loss in surface smoothness due to the relative slide with the magnetic tape.
    Type: Grant
    Filed: November 8, 1991
    Date of Patent: March 1, 1994
    Assignee: Hitachi Metals, Ltd.
    Inventors: Hiroshi Tomishima, Toshikazu Nishiyama, Nobuyuki Yamada, Noriyuki Kumasaka, Mitsuo Abe
  • Patent number: 5057374
    Abstract: Nonmagnetic substrate material containing 67 to about 89.9 mol % of MnO, 10 to 33 mol % of NiO, and at least 0.1 mol % but not more than 10 mol % of a material selected from the group of CaO, ZrO.sub.2, V.sub.2 O.sub.5, Y.sub.2 O.sub.3, and Cu and having a rock salt-type crystalline structure.
    Type: Grant
    Filed: September 15, 1988
    Date of Patent: October 15, 1991
    Assignee: Hitachi Metals, Ltd.
    Inventors: Kazuhiro Tsuchiya, Toshikazu Nishiyama, Hiroshi Tomishima
  • Patent number: 4805059
    Abstract: A magnetic head having a magnetic alloy film superposed on a nonmagnetic substrate. The nonmagnetic substrate material contains 67 to about 89.9 mol % of MnO, 10 to 33 mol % of NiO, and at least 0.1 mol % but not more than 10 mol % of a material selected from the group of CaO, ZrO.sub.2, V.sub.2 O.sub.5, Y.sub.2 O.sub.3, and Cu and has a rock salt-type crystalline structure.
    Type: Grant
    Filed: July 21, 1986
    Date of Patent: February 14, 1989
    Assignee: Hitachi Metals, Ltd.
    Inventors: Kazuhiro Tsuchiya, Toshikazu Nishiyama, Hiroshi Tomishima
  • Patent number: 4028144
    Abstract: A semi-hard magnetic alloy is described which consists of, by weight, 15-50% Co, 5-25% Ni, 1-9% Cr, balance Fe and incidental impurities and containing further a positive amount of up to 10% Cu or Ti. The alloy is characterized by exhibiting composite hysteresis characteristics as shown in FIG. 3 of the drawings. The alloy may be produced by a repetitive cold-working and subsequent annealing steps, the annealing step being carried out at temperatures of between 450.degree. and 750.degree. C.
    Type: Grant
    Filed: August 14, 1975
    Date of Patent: June 7, 1977
    Assignee: Nippon Telegraph and Telephone Public Corporation
    Inventors: Hiroshi Tomishima, Toshio Takahashi, Kenichi Ono, Kazuhiro Kumasaka