Patents by Inventor Ryuji Shirahata

Ryuji Shirahata 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: 4354908
    Abstract: A process for the production of a magnetic recording member which comprises effecting electric field vapor deposition under conditions such that the angle of incidence at which the vapor beam of a ferromagnetic metal strikes a support is at least about 50.degree. and the electric field between the support and a vaporization source is at least about 5 kv/m.
    Type: Grant
    Filed: July 11, 1978
    Date of Patent: October 19, 1982
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto, Yasuo Tamai, Masaaki Suzuki
  • Patent number: 4333985
    Abstract: A magnetic recording medium is described comprising a protective layer including at least one substance selected from the group consisting of poly(paraxylylene), poly(monochloroparaxylylene), and poly(dichloroparaxylylene) formed on a magnetic recording layer comprising a thin ferromagnetic metal film.
    Type: Grant
    Filed: April 24, 1981
    Date of Patent: June 8, 1982
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Akio Yanai, Tatsuji Kitamoto
  • Patent number: 4286299
    Abstract: A magnetic head assembly for recording and playing back information on a recording medium in a vertically magnetized mode. Main and auxiliary heads are provided opposite one another with the recording medium passing therebetween. The main head includes a core of material exhibiting a magnetoresistance effect to which core are attached leads which carry the output play back signal. The auxiliary head has a magnetic core around which is wrapped a winding carrying the recording current. The recorded information patterns have their primary magnetic field components perpendicular to the surface of the recording medium.
    Type: Grant
    Filed: October 11, 1979
    Date of Patent: August 25, 1981
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto
  • Patent number: 4260466
    Abstract: A method of producing a magnetic recording layer on a support comprising simultaneously depositing a ferromagnetic material and a polymer on a support using a vapor deposition technique such as vacuum deposition, sputtering, etc., thereby to produce thereon a magnetic recording layer of a composite film of the ferromagnetic material and the polymer. A further embodiment for producing a magnetic recording layer comprises simultaneously depositing a ferromagnetic material and a monomer or oligomer on the support using a vapor deposition technique, polymerizing the deposited layer, e.g., using a polymerization catalyst or by applying ionizing or electromagnetic rays thereto, to form a composite film of the ferromagnetic material and the polymer. The magnetic recording layer thus obtained in either embodiment can be used for high density recording.
    Type: Grant
    Filed: February 24, 1977
    Date of Patent: April 7, 1981
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto, Yasuyuki Yamada, Goro Akashi
  • Patent number: 4250225
    Abstract: A magnetic recording medium excellent in adhesiveness and surface property is produced by a process comprising treating the surface of a plastic substrate by glow discharge, then subjecting the substrate to a surface activating treatment and forming a magnetic metallic plating layer on the surface of the substrate by an electroless plating method.
    Type: Grant
    Filed: July 24, 1978
    Date of Patent: February 10, 1981
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto, Masaaki Suzuki, Hiroshi Amari
  • Patent number: 4226681
    Abstract: This invention relates to a process for the production of a magnetic recording medium, which comprises heating a substrate or subbing layer containing copper as a main component at a temperature of about 100.degree. to 350.degree. C. and, at the same time, vapor depositing in vacuum a ferromagnetic metal containing cobalt as a main component on the substrate or subbing layer to thus form a magnetic recording layer.
    Type: Grant
    Filed: June 19, 1978
    Date of Patent: October 7, 1980
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto
  • Patent number: 4172171
    Abstract: This invention relates to a magnetic recording medium which comprises a non-magnetic support, at least one magnetic recording layer containing a magnetic powder and a binder and being provided on the support and a ferromagnetic metal thin film with a thickness of at most 1 micron, being provided on the magnetic recording layer by an oblique incidence vapor deposition method with an electric field. This multi-layer magnetic recording medium exhibits various excellent magnetic recording performances.
    Type: Grant
    Filed: November 4, 1977
    Date of Patent: October 23, 1979
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Masaaki Suzuki, Ryuji Shirahata
  • Patent number: 4153920
    Abstract: This invention relates to a magnetic recording medium comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, in which the surface roughness of the support is 0.10 .mu.m or less and the period of the surface roughness is v/10.sup.6 .mu.m or less where v represents a relative speed between a magnetic head and magnetic recording medium by .mu.m/sec. In the case of providing an undercoated layer between the magnetic recording layer and non-magnetic flexible support, the surface roughness of the undercoated layer is adjusted to 0.10 .mu.m or less and the period of the surface roughness is adjusted to v/10.sup.6 .mu.m or less.
    Type: Grant
    Filed: November 21, 1977
    Date of Patent: May 8, 1979
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto, Masaaki Suzuki, Shin-ichiro Dezawa
  • Patent number: 4128691
    Abstract: The process for the production of a magnetic recording medium by electroless plating comprises carrying out the plating in a plating aqueous solution containing at least one ferromagnetic metal ion, barium ion and hypophosphite ion as a reducing agent, and thus forming a magnetic metal thin film.
    Type: Grant
    Filed: July 27, 1976
    Date of Patent: December 5, 1978
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto, Masaaki Suzuki
  • Patent number: 4097650
    Abstract: This invention relates to a magnetic recording medium comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, in which the surface roughness of the support is 0.10 .mu.m or less and the period of the surface roughness is v/10.sup.6 .mu.m or less where v represents a relative speed between a magnetic head and magnetic recording medium by .mu.m/sec. In the case of providing an undercoated layer between the magnetic recording layer and non-magnetic flexible support, the surface roughness of the undercoated layer is adjusted to 0.10 .mu.m or less and the period of the surface roughness is adjusted to v/10.sup.6 .mu.m or less.
    Type: Grant
    Filed: August 24, 1976
    Date of Patent: June 27, 1978
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto, Masaaki Suzuki, Shin-ichiro Dezawa
  • Patent number: 4089993
    Abstract: This invention relates to a method of forming a metallic thin film on a plastic substrate by electroless plating, which comprises providing an undercoated layer consisting essentially of polyvinylidene chloride or vinylidene chloride copolymer on the surface of the plastic substrate and then subjecting to a surface activating treatment and electroless plating.
    Type: Grant
    Filed: October 19, 1976
    Date of Patent: May 16, 1978
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Masaaki Suzuki, Yasuyuki Yamada, Tatsuji Kitamoto, Shin-ichiro Dezawa
  • Patent number: 4087582
    Abstract: A magnetic recording medium comprising a support, a magnetic recording layer comprising a thin film of a ferromagnetic metal on the support, and at least one monomolecular layer comprising a saturated fatty acid or a metal salt thereof on the surface of the magnetic recording layer.
    Type: Grant
    Filed: November 4, 1974
    Date of Patent: May 2, 1978
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto
  • Patent number: 4086374
    Abstract: An improved method of making a magnetic recording material comprises providing a ferromagnetic metal thin layer which has uniaxial anisotropy in any direction on a web by means of plating.A plating solution is jetted onto the web through holes in a conveying pipe set in a plating bath. The web is then moved from the vicinity of the conveying pipe by the spouting force of the plating solution, and then conveyed along a helical path about the conveying pipe without contacting the surface of conveying pipe. Plating occurs while applying a magnetic field to the web.
    Type: Grant
    Filed: April 26, 1976
    Date of Patent: April 25, 1978
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Masaaki Suzuki, Ryuji Shirahata, Masashi Aonuma, Tatsuji Kitamoto
  • Patent number: 4072781
    Abstract: The magnetic recording medium comprising a nonmagnetizable base having provided thereon a magnetizable layer by electroless plating, said magnetizable layer containing at least one ferromagnetic metal, phosphorus and at least one of copper, lead and silicon.
    Type: Grant
    Filed: November 3, 1975
    Date of Patent: February 7, 1978
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Masaaki Suzuki, Tatsuji Kitamoto
  • Patent number: 4002546
    Abstract: An improved method of making a magnetic recording medium with excellent coercive force and rectangular ratio is provided by means of an ion plating technique. A support and an evaporation source of a magnetic Co-Si alloy are placed in an ion plating apparatus which is filled with an inert gas and kept at low vacuum. High voltage is then applied between the support and the evaporation source such that the former has a negative polarity and the latter a positive polarity, thereby causing a glow discharge zone in the apparatus. The magnetic alloy is evaporated into the glow discharge zone from the source to form a magnetic thin film on the support. Such a magnetic thin film can have a coercive force of 750 Oe or more and a rectangular ratio of 0.80 or more and can be used as a magnetic recording medium.
    Type: Grant
    Filed: December 10, 1975
    Date of Patent: January 11, 1977
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Tatsuji Kitamoto, Masaaki Suzuki
  • Patent number: 3993824
    Abstract: A magnetic recording member comprising a non-magnetic support having a magnetic recording layer on one side of the non-magnetic support and a lubricating layer on the other side of the non-magnetic support in which the lubricating layer comprises a liquid or semi-solid lubricant or a liquid or semi-solid lubricant, and an organic binder.
    Type: Grant
    Filed: February 18, 1975
    Date of Patent: November 23, 1976
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryuji Shirahata, Yasuyuki Yamada, Tatsuji Kitamoto