Patents by Inventor Fumihiro Tokunaga

Fumihiro Tokunaga 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: 5057373
    Abstract: A magnetic recording medium comprising a nonmagnetic support having thereon a magnetic layer comprising a binder and ferromagnetic particles dispersed therein, wherein the binder comprises (a) a vinyl chloride resin, (b) a phenoxy resin, (c) a polycarbonate polyurethane resin and (d) a polyisocyanate; and said magnetic layer further comprises at least one lubricating agent selected from the group consisting of polyalkylnenoxide alkylphosphate, an alkali salt thereof, and lecithin.
    Type: Grant
    Filed: March 30, 1989
    Date of Patent: October 15, 1991
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Fumihiro Tokunaga, Jun Nakagawa, Tsutomu Okita, Toshio Kawamata
  • Patent number: 4970121
    Abstract: A magnetic recording medium comprising a nonmagnetic support having thereon a magnetic layer comprising ferromagnetic particles dispersed in a binder comprising a mixture of a polycarbonate polyurethane and a phenoxy resin in a weight ratio of from about 1.5:1 to 5:1.
    Type: Grant
    Filed: August 8, 1988
    Date of Patent: November 13, 1990
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Fumihiro Tokunaga, Jun Nakagawa, Tsutomu Okita, Toshio Kawamata, Kazuo Hasumi
  • Patent number: 4678706
    Abstract: A magnetic recording medium is described, comprising a non-magnetic support, a magnetic recording layer on one side of the support, and a backing layer on the opposite side of the support to the magnetic recording layer, wherein said backing layer comprising a binder and a powder dispersed in the binder, wherein the powder is a powdered oxide represented by the formula M.sup.1.M.sup.2.O.sub.2+x (wherein M.sup.1 is at least one element selected from the group consisting of Ba, Sr, Pb and Ca, M.sup.2 is at least one element selected from the group consisting of Ti, Zr and Sn, and x is in the range of from 0 to 0.9) or a mixture of said powdered oxide and carbon black. This magnetic recording medium has a decreased coefficient of friction, is free from formation of scratches, has good durability, and furthermore, maintains good S/N characteristics.
    Type: Grant
    Filed: October 24, 1985
    Date of Patent: July 7, 1987
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Fumihiro Tokunaga, Takamitsu Asai, Masaaki Fujiyama
  • Patent number: 4656088
    Abstract: A magnetic recording medium is disclosed. The medium comprises a non-magnetic support having provided thereon a magnetic layer comprising a binder, a magnetic powder and a powder of an oxide represented by the formula:M-1.multidot.M-2.multidot.O.sub.2+xwherein M-1 is at least one of barium, strontium, lead and calcium; M-2 is at least one member of titanium, zirconium and tin; and x represents a number of from 0 to 0.9. The medium has a high S/N ratio and improved wear resistance and causes only moderate wear of a magnetic head.
    Type: Grant
    Filed: August 23, 1985
    Date of Patent: April 7, 1987
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Fumihiro Tokunaga, Takamitsu Asai, Masaaki Fujiyama
  • Patent number: 4542085
    Abstract: A negative working light-sensitive composition and a lithographic printing plate using the composition are described. The printing plate is comprised of a hydrophilic support and a thin layer of a negative working light-sensitive composition on the support. The light-sensitive composition contains a light-sensitive diazo compound and a compound capable of increasing absorption over the light-sensitive wavelength region of the composition with increasing exposure time.
    Type: Grant
    Filed: June 2, 1983
    Date of Patent: September 17, 1985
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Hiroshi Takahashi, Akira Nishioka, Fumihiro Tokunaga, Yoshimasa Aotani, Koichiro Aono