Patents by Inventor Katsumi Ryoke

Katsumi Ryoke 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: 4614685
    Abstract: A magnetic recording medium comprised of a non-magnetic support base having a magnetic layer provided thereon is disclosed. The magnetic layer is comprised of carbon black having an average particle size of 30 to 50 m.mu. and an iron oxide which contains Co. The iron oxide containing the Co has a specific surface area of 25 m.sup.2 /g or more. The carbon black and the iron oxide containing the Co are dispersed in a binder. By utilizing the particular type of carbon black in combination with the particular iron oxide containing Co in the magnetic layer it is possible to greatly improve the running characteristics of the magnetic recording medium as well as obtain an improved RF output.
    Type: Grant
    Filed: April 9, 1984
    Date of Patent: September 30, 1986
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Katsumi Ryoke, Kenichi Masuyama, Eiichi Tadokoro
  • Patent number: 4582754
    Abstract: A magnetic recording medium comprising a support having provided thereon a magnetic recording layer containing (1) a cobalt-containing iron oxide, (2) graphite, and (3) a copolymer of vinyl chloride, vinyl acetate and maleic acid.
    Type: Grant
    Filed: July 26, 1984
    Date of Patent: April 15, 1986
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Katsumi Ryoke, Shinobu Iida, Masaaki Fujiyama, Eiichi Tadokoro
  • Patent number: 4554220
    Abstract: A magnetic recording medium is described, comprising a non-magnetic support base having positioned thereon a magnetic layer and optionally a non-magnetic layer, wherein at least one layer of the magnetic and non-magnetic layers contains an ester derived from pentaerythritol and/or its condensate and a fatty acid and/or a resin acid. This recording medium has superior surface properties and can be satisfactorily used in tape decks.
    Type: Grant
    Filed: August 2, 1983
    Date of Patent: November 19, 1985
    Assignees: Fuji Photo Film Co., Ltd., Nisshin Oil Mills, Ltd.
    Inventors: Nobuyuki Yamamoto, Katsumi Ryoke, Nobuo Tsuji, Yuzo Higaki, Toshihisa Okamura
  • Patent number: 4552799
    Abstract: A magnetic recording medium comprised of a non-magnetic support base having provided thereon a magnetic recording layer is disclosed. The medium also has position thereon a compound selected from the group consisting of carboxylic acids and carboxylic acid derivatives, the compound being present on an edge portion of the medium. The medium also includes an additional lubricant on the middle part of the medium, the additional lubricant being selected from the group consisting of alphatic acid esters, alphatic acids, silicons and phosphoric acid esters. By utilizing two different types of lubricants on different portions of the medium it is possible to obtain improved lubricating properties and thus improve runnability with respect to the operation of the magnetic recording medium.
    Type: Grant
    Filed: April 23, 1984
    Date of Patent: November 12, 1985
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Katsumi Ryoke, Shinobu Iida, Masaaki Fujiyama, Eiichi Tadokoro
  • Patent number: 4552798
    Abstract: A magnetic recording medium comprised of a support base having a magnetic recording layer positioned thereon is disclosed. The recording medium has positioned an aliphatic acid ester compound on an edge portion of the surface of the recording layer. By utilizing the aliphatic acid ester the recording medium has less audio output variation and the tracking control of the medium is improved. Further, the medium has good running characteristics and excellent sensitivity.
    Type: Grant
    Filed: February 7, 1984
    Date of Patent: November 12, 1985
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Katsumi Ryoke, Yasuhiro Abe, Shinobu Iida, Eiichi Tadokoro
  • Patent number: 4546038
    Abstract: A magnetic recording medium is disclosed which is comprised of a non-magnetic support having a magnetic layer provided thereon. The magnetic layer is comprised of two different types of carbon black having different particle sizes, a lubricant which is liquid at room temperature, a ferromagnetic powder all dispersed in a binder. A carbon black (1) has an average particle size smaller than 50 m.mu. and a carbon black (2) has an average particle size of larger than 120 m.mu.. The carbon black is present in a weight ratio of (1)/(2) within the range of 50/50 to 97/3. The magnetic recording medium has improved electromagnetic properties and running durability. In addition, the material provides an improved S/N ratio and an improved coefficient of friction.
    Type: Grant
    Filed: April 29, 1983
    Date of Patent: October 8, 1985
    Assignee: Fuji Photo Film Company, Limited
    Inventors: Nobutaka Yamaguchi, Masaaki Fujiyama, Katsumi Ryoke, Eiichi Tadokoro
  • Patent number: 4539257
    Abstract: A magnetic recording medium comprised of a nonmagnetic support base having a magnetic layer provided thereon is disclosed. The magnetic layer includes ferromagnetic particles dispersed in a binder in combination with carbon black particles. The carbon black particles have an average primary particle size in the range of 30 m.mu. to 50 m.mu.. Further, the carbon black is capable of the adsorption of 120 ml or more of dibutyl phthalate per 100 g of carbon black. By utilizing the particular carbon black of the present invention it is possible to obtain a magnetic recording medium having improved running properties.
    Type: Grant
    Filed: April 13, 1984
    Date of Patent: September 3, 1985
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Katsumi Ryoke, Kenichi Masuyama, Takashi Yoneyama, Norio Nasu, Eiichi Tadokoro
  • Patent number: 4499121
    Abstract: A method for producing a magnetic recording medium is disclosed. The method involves providing a ferromagnetic coating layer on a non-magnetic support base to produce a coated base. The coated base is then subjected to an atmosphere having a RH of 60% or more, prior to or during a subsequent calendering treatment. The recording medium produced has excellent surface smoothness and improved electromagnetic properties. The method is advantageous in that a substantially long period of time may pass between the coating of the ferromagnetic layer on the support and the calendering treatment without having undesirable effects on the magnetic recording medium produced.
    Type: Grant
    Filed: May 4, 1983
    Date of Patent: February 12, 1985
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Nobutaka Yamaguchi, Masaaki Fujiyama, Sugihiko Tada, Eiichi Tadokoro, Katsumi Ryoke, Masahiro Utsumi, Masami Suzuki
  • Patent number: 4497864
    Abstract: A magnetic recording medium is disclosed. The medium is comprised of a support base having coated thereon a magnetic layer comprised of ferromagnetic particles dispersed in a binder and further comprised of at least one anhydrosorbitol di- and/or tetra-fatty acid non-hydroxy ester. By including the particularly disclosed fatty acid non-hydroxy ester the running properties of the magnetic recording medium are greatly improved.
    Type: Grant
    Filed: July 6, 1983
    Date of Patent: February 5, 1985
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Katsumi Ryoke, Nobutaka Yamaguchi, Takashi Yoneyama, Eiichi Tadokoro
  • Patent number: 4304852
    Abstract: A silver halide photographic light-sensitive material is described containinga film-forming water-soluble polymer derived from a monomer including a carboxylic acid group;a compound of the formula (I) ##STR1## wherein A is ##STR2## or a chemical bond; R is a saturated or unsaturated hydrocarbon group having from 8 to 22 carbon atoms when A is a chemical bond, and a saturated or unsaturated hydrocarbon group having from 7 to 21 carbon atoms whenA is ##STR3## R.sub.5 is hydrogen, a methyl group, or an ethyl group; B is --COO.sup..crclbar. or --SO.sub.3.sup..crclbar. ; R.sub.1 and R.sub.2 are each an alkyl group or hydroxyalkyl group having from 1 to 18 carbon atoms, or a polyalkylene oxide chain group; R.sub.3 and R.sub.4 are each hydrogen or an alkyl group having from 1 to 4 carbon atoms; n is an integer of from 2 to 8; and x is 0 or 1; anda compound of the formula (II) ##STR4## wherein A, B, R.sub.1, R.sub.2, R.sub.3, R.sub.
    Type: Grant
    Filed: September 19, 1980
    Date of Patent: December 8, 1981
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Naohiko Sugimoto, Shinzo Kishimoto, Katsumi Ryoke, Masakazu Yoneyama, Nobuhisa Sekiguchi