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).
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Patent number: 4600638Abstract: A magnetic recording medium is disclosed, which comprises a non-magnetic support having, on opposite surfaces thereof, a magnetic recording layer containing magnetic particles and a backing layer containing carbon black and other inorganic particles and a binder having a thickness of not more than 2.mu., the backing layer containing (a) carbon black having an average particle size of 60 to 120 m.mu. and (b) other inorganic particles having an average particle size of 20 to 100 m.mu..Type: GrantFiled: May 15, 1984Date of Patent: July 15, 1986Assignee: Fuji Photo Film Co., Ltd.Inventors: Tadashi Ishikuro, Ryuji Shirahata, Takahito Miyoshi, Masaaki Fujiyama
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Patent number: 4588636Abstract: A magnetic recording medium having a thin ferromagnetic metal film formed on a non-magnetic base by vacuum vapor deposition or ion plating is disclosed. The thin ferromagnetic metal film is based on Co and contains 0.05 to 3.0 wt % of Mg.Type: GrantFiled: February 12, 1982Date of Patent: May 13, 1986Assignee: Fuji Photo Film Co., Ltd.Inventors: Ryuji Shirahata, Akio Yanai, Tatsuji Kitamoto
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Patent number: 4588656Abstract: A magnetic recording medium comprising a substrate, a thin magnetic metal film having spaced-apart columnar grains deposited on the substrate, and an organic polymer formed in the space between the columnar grains and integrated therewith. The medium is prepared by impregnating the spaces between the columnar grains with organic monomers or oligomers and polymerizing them in the spaces.Type: GrantFiled: February 25, 1982Date of Patent: May 13, 1986Assignee: Fuji Photo Film Co., Ltd.Inventors: Tatsuji Kitamoto, Ryuji Shirahata, Yasuyuki Yamada, Goro Akashi
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Patent number: 4582746Abstract: Weather resistance and lubricity of a magnetic recording medium comprising a non-magnetic support having provided thereon a vapor deposited magnetic thin film mainly composed of cobalt, nickel and oxygen can be improved by limiting the amount of nickel and the number of oxygen atoms to a specific value and by providing a plasma polymerized layer on the magnetic thin film.Type: GrantFiled: March 1, 1984Date of Patent: April 15, 1986Assignee: Fuji Photo Film Co., Ltd.Inventors: Ryuji Shirahata, Tatsuji Kitamoto
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Patent number: 4578311Abstract: A magnetic recording medium is disclosed which comprises a non-magnetic support having provided on opposite surface thereof a magnetic recording layer, and a backing layer containing carbon black and a binder, said carbon having an average particle size of not less than 150 m.mu. and the weight ratio of carbon black and the binder being 1:3.0 to 1:10.Type: GrantFiled: May 29, 1984Date of Patent: March 25, 1986Assignee: Fuji Photo Film Co., Ltd.Inventors: Tadashi Ishikuro, Ryuji Shirahata, Takahito Miyoshi, Masaaki Fujiyama
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Patent number: 4557948Abstract: A process for producing a magnetic recording material comprising a support having a thin metal film layer provided thereon is described, the process comprising the steps of (1) coating a thin magnetic metal film having a water contact angle of at least 25.degree. with a polymer solution to form a thin polymer layer, drying the thin polymer layer, and providing a lubricant on the thin polymer layer, or (2) coating the thin magnetic metal film with a lubricant-containing polymer solution to form a lubricant-containing polymer layer, and drying the lubricant-containing polymer layer.Type: GrantFiled: August 6, 1984Date of Patent: December 10, 1985Assignee: Fuji Photo Film Co., Ltd.Inventors: Nobuyuki Yamamoto, Masao Yabe, Yasuo Nishikawa, Akio Yanai, Ryuji Shirahata, Kyoichi Naruo
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Patent number: 4546725Abstract: A magnetic recording medium manufacturing apparatus is comprised of a cooling rotary cylinder can and a small roller, arranged adjacent to each other. A flexible endless belt is laid over the can and roller and carries a tape-shaped support. A ferromagnetic material, evaporated from an evaporation source disposed below the can and roller, is vacuum-deposited onto the tape-shaped support.Type: GrantFiled: March 8, 1984Date of Patent: October 15, 1985Assignee: Fuji Photo Film Co., Ltd.Inventors: Ryuji Shirahata, Masaru Sekine, Goro Akashi
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Patent number: 4526131Abstract: A magnetic recording medium manufacturing apparatus is comprised of a cooling rotary cylinder can and a small roller, arranged adjacent to each other, and with the small roller being swingable about the central axis of the can. A flexible endless belt is laid over the can and roller and carries a tape-shaped support. A ferromagnetic material, evaporated from an evaporation source disposed below the can and roller, is vacuum-deposited onto the tape-shaped support.Type: GrantFiled: March 8, 1984Date of Patent: July 2, 1985Assignee: Fuji Photo Film Co., Ltd.Inventors: Ryuji Shirahata, Masaru Sekine, Goro Akashi
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Patent number: 4511594Abstract: A system of manufacturing a magnetic recording medium in which a magnetic metal or alloy is heated and evaporated by an electron beam gun so that vacuum-evaporated magnetic film is formed on a non-organic or organic macromolecular base. A plasma generating coil is disposed near an evaporating source and an electron beam passes through the hollow portion of the coil in preferably a direction coaxial with the axis of the coil. High frequency power is applied to the coil and vacuum deposition is carried out with a plasma generated thereby. The flow of vapor of magnetic metal or alloy is applied obliquely to the base and an oxidation gas is introduced into a vacuum container for forming the magnetic film.Type: GrantFiled: January 18, 1983Date of Patent: April 16, 1985Assignee: Fuji Photo Film Co., Ltd.Inventors: Akio Yanai, Ryuji Shirahata
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Patent number: 4503119Abstract: A magnetic recording medium which is characterized by a lubricant present in channels diagonally extending through a magnetic metal thin film having a columnar structure formed by vapor deposition; this medium possesses improved running properties and abrasion resistance which last for an extended period of time.Type: GrantFiled: November 30, 1981Date of Patent: March 5, 1985Assignee: Fuji Photo Film Co., Ltd.Inventors: Ryuji Shirahata, Yasuyuki Yamada, Tatsuji Kitamoto, Goro Akashi
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Patent number: 4477489Abstract: In a method of making a magnetic recording medium by causing a flow of vapor obtained by evaporating a magnetic metal deposition material to impinge and deposit on a moving substrate at an oblique angle with respect to the moving substrate, the substrate is moved so that the incident angle of the vapor flow with respect to the substrate continuously changes from the maximum incident angle to the minimum incident angle, and an oxidizing gas is introduced in the vicinity of the substrate and near the maximum incident angle portion or the minimum incident angle portion of the vapor flow during the formation of a thin ferromagnetic film on the substrate. The maximum incident angle is preferably between 60.degree. and 90.degree., and the minimum incident angle between 30.degree. and 75.degree..Type: GrantFiled: September 1, 1982Date of Patent: October 16, 1984Assignee: Fuji Photo Film Co., Ltd.Inventors: Akio Yanai, Ryuji Shirahata, Tatsuji Kitamoto
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Patent number: 4474832Abstract: A method for preparing a magnetic recording medium is disclosed. The method involves forming a thin magnetic layer on a polyester film by means of a vapor deposition or plating method, continually moving the film while maintaining it at a tension of 400 g/mm.sup.2 or less and contacting the moving film with a heating device at a temperature within the range of 70.degree. to 200.degree. C. for a period of time within the range of 0.1 to 30 seconds. The method provides a non-binder type magnetic recording medium having improved skew characteristics without formation of curls.Type: GrantFiled: March 16, 1983Date of Patent: October 2, 1984Assignee: Fuji Photo Film Company LimitedInventors: Ryuji Shirahata, Masaru Sekine, Noburo Hibino
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Patent number: 4454836Abstract: An apparatus for vacuum evaporating magnetic material onto a base. Cylindrical cans are disposed parallel to one another and rotated either in the same or opposite directions. A tape-shaped base is wound around the cans passing from an upper vacuum chamber to a lower vacuum chamber. A vacuum evaporation source is positioned in the lower chamber and directed to the tape-shaped base in a predetermined area on both sides of a gap between the cans or a line contact area between the cans.Type: GrantFiled: May 26, 1983Date of Patent: June 19, 1984Assignee: Fuji Photo Film Co., Ltd.Inventors: Goro Akashi, Ryuji Shirahata
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Patent number: 4448843Abstract: A magnetic recording medium is described wherein a layer comprising mainly a polyurethane resin, vinylidene chloride copolymer, or a cellulose derivative is formed on the surface of a vapor-deposited ferromagnetic metal layer on a substrate.Type: GrantFiled: April 10, 1981Date of Patent: May 15, 1984Assignee: Fuji Photo Film Co., Ltd.Inventors: Yasuyuki Yamada, Ryuji Shirahata, Akio Yanai, Tatsuji Kitamoto
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Patent number: 4446816Abstract: An apparatus for manufacturing a magnetic recording medium using vacuum-deposition from an evaporated metal source having a very high efficiency and uniform deposition. The support onto which the magnetic film is to be evaporated is guided and conveyed along a curved path above a molten metal evaporating source at a substantially constant speed. The curved path is shaped such that evaporated metal flow lines connecting a central point on the evaporation surface of the molten metal in the evaporating source to corresponding intersection points on the support form the same angle of incidence with respect to the longitudinal direction of the support for all positions along the support where the film is to be deposited. Endless belt structures including guide rollers and magnets are used to form rising and falling paths for conveying the support along the desired curved path.Type: GrantFiled: May 3, 1983Date of Patent: May 8, 1984Assignee: Fuji Photo Film Co., Ltd.Inventors: Tatsuji Kitamoto, Ryuji Shirahata
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Patent number: 4414271Abstract: A magnetic recording medium comprising a substrate, a thin magnetic metal film having spaced-apart columnar grains deposited on the substrate, and a crosslinked organic polymer formed from a polymerizable organic compound and a curing agent in the spaces between the columnar grains and integrated therewith. The medium is prepared by impregnating the spaces between the columnar grains with a polymerizable organic compound and a curing agent and curing them in the spaces by the crosslinking reaction.Type: GrantFiled: February 25, 1982Date of Patent: November 8, 1983Assignee: Fuji Photo Film Co., Ltd.Inventors: Tatsuji Kitamoto, Ryuji Shirahata, Yasuyuki Yamada, Goro Akashi
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Patent number: 4412507Abstract: A magnetic recording medium manufacturing device in which a flexible belt-shaped support is conveyed above a molten metal vaporizing source substantially at a constant speed while a magnetic film is formed on a surface of the support by vacuum deposition. The support is guided by transporting means such that the support is curved above the molten metal vaporizing source along a path wherein metal vapor flow lines connecting the center of the molten metal vaporizing source to points on the surface of the support form a constant angle of incidence with the longitudinal direction of the support. An adjusting mechanism is provided to change the angle of incidence by moving the transporting means along lines parallel to the metal vapor flow lines.Type: GrantFiled: July 20, 1981Date of Patent: November 1, 1983Assignee: Fuji Photo Film Co., Ltd.Inventors: Tatsuji Kitamoto, Ryuji Shirahata
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Patent number: 4410565Abstract: A magnetic recording medium comprising a substrate, a thermoplastic prime coat provided thereon, and a ferromagnetic metal layer having columnar grains which at least partially penetrate into the prime coat from the top thereof and are integrated therewith. The medium is prepared by applying a prime coat onto a substrate, forming a magnetic metal layer having columnar grains by vapor deposition, and then heating and pressing the obtained combination.Type: GrantFiled: February 25, 1982Date of Patent: October 18, 1983Assignee: Fuji Photo Film Co., Ltd.Inventors: Tatsuji Kitamoto, Ryuji Shirahata, Yasuo Tamai
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Patent number: 4403002Abstract: A method and apparatus for vacuum evaporating magnetic material onto a base. Cylindrical cans are disposed parallel to one another and rotated either in the same or opposite directions. A tape-shaped base is wound around the cans passing from an upper vacuum chamber to a lower vacuum chamber. A vacuum evaporation source is positioned in the lower chamber and directed to the tape-shaped base in a predetermined area on both sides of a gap between the cans or a line contact area between the cans.Type: GrantFiled: November 23, 1982Date of Patent: September 6, 1983Assignee: Fuji Photo Film Co., Ltd.Inventors: Goro Akashi, Ryuji Shirahata
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Patent number: 4395439Abstract: A method and apparatus for manufacturing a magnetic recording medium using vacuum-deposition from an evaporated metal source having a very high efficiency and uniform deposition. The support onto which the magnetic film is to be evaporated is guided and conveyed along a curved path above a molten metal evaporating source at a substantially constant speed. The curved path is shaped such that evaporated metal flow lines connecting a central point on the evaporation surface of the molten metal in the evaporating source to corresponding intersection points on the support form the same angle of incidence with respect to the longitudinal direction of the support for all positions along the support where the film is to be deposited. Endless belt structures including guide rollers and magnets are used to form rising and falling paths for conveying the support along the desired curved path.Type: GrantFiled: May 19, 1981Date of Patent: July 26, 1983Assignee: Fuji Photo Film Co., Ltd.Inventors: Tatsuji Kitamoto, Ryuji Shirahata