Patents by Inventor Tadashi Ido
Tadashi Ido 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: 5104750Abstract: In the magnetic recording medium according to the present invention comprising a magnetic recording medium layer where a magnetic paint containing Ba ferrite magnetic powder is coated on the substrate, Hc in the oriented direction ranging from 900 to 1500 Oe, the squareness in the oriented direction being 0.80 or more, and the ratio Hr(90.degree.)/Hr(0.degree.) of the remanence coercive force Hr(0.degree.) in the oriented direction (0.degree.) and the remanence coercive force Hr (90.degree.) in the direction (90.degree.) perpendicular to the oriented direction ranging from 1<Hr(90.degree.)/Hr(0.degree.).ltoreq.2.6-10.sup.-3. Hc are controllable.Type: GrantFiled: March 30, 1990Date of Patent: April 14, 1992Assignee: Kabushiki Kaisha ToshibaInventors: Osamu Kubo, Tutomu Nomura, Tadashi Ido
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Patent number: 5077146Abstract: Disclosed is a magnetic powder for high-density magnetic recording, formed of a substituted hexagonal ferrite possessing an average particle diameter in the range of 0.01 to 0.2 .mu.m and a coercivity in the range of 200 to 2,000 Oe and characterized by the fact that the substituted hexagonal ferrite has at least 0.05 to 0.5 atom of at least one element selected from the group consisting of Zr and Hf per chemical formula and at least one element selected from among the elements other than Zr and Hf substituted for part of the Fe atom of the ferrite, and a magnetic recording medium of the present invention comprises a substrate and the magnetic powder mentioned above deposited on the substrate. Since the magnetic powder comprises very minute particles, the magnetic powder and the magnetic recording medium are capable of high-density recording.Type: GrantFiled: September 29, 1988Date of Patent: December 31, 1991Assignee: Kabushiki Kaisha ToshibaInventors: Osamu Kubo, Tutomu Nomura, Tadashi Ido, Hirotaka Yokoyama
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Patent number: 4837092Abstract: A magnetic recording powder comprising a hexagonal barium ferrite substituted with a coercive force control element. This magnetic powder is preliminarily treated with sulfate ion-containing water so as to convert any free barium ions in the magnetic powder to a water insoluble compound such as BaSO.sub.4 or BaS.sub.2 O.sub.7. There is also proposed a magnetic recording medium having a magnetic layer containing such a magnetic powder as mentioned above.Type: GrantFiled: August 12, 1987Date of Patent: June 6, 1989Assignee: Kabushiki Kaisha ToshibaInventors: Hirotaka Yokoyama, Tadashi Ido, Tatsumi Maeda, Shunji Kurisu
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Patent number: 4699771Abstract: A matnetic recording powder comprising a hexagonal barium ferrite substituted with a coercive force control element. This magnetic powder is preliminarily treated with sulfate ion-containing water so as to convert any free barium ions in the magnetic powder to a water insoluble compound such as BaSO.sub.4 or BaS.sub.2 O.sub.7. There is also proposed a magnetic recording medium having a magnetic layer containing such a magnetic powder as mentioned above.Type: GrantFiled: March 26, 1985Date of Patent: October 13, 1987Assignee: Kabushiki Kaisha ToshibaInventors: Hirotaka Yokoyama, Tadashi Ido, Tatsumi Maeda, Shunji Kurisu
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Patent number: 4636433Abstract: A magnetic powder for magnetic recording media comprises a hexagonal crystalline system ferrite containing, as essential components for said hexagonal crystalline system ferrite, iron and oxygen, and at least one of the elements selected from the group of Ba, Sr, Ca and Pb, said iron being substituted by at least one of the elements selected from the group of Ti, Co, Ni, Mn, Cu, Zn, In, Ge, Nb, Zr and Sb; and at least one of Ba, Sr, Ca, Pb being substituted by at least one of the rare earth elements selected from the group of Ce, Pr, Nd, Pm, Sm and Eu. The magnetic powder has a mean particle size of 0.01 to 0.3 .mu.m and a coercive force of 200 and 2000 Oe. The magnetic powder is improved in its saturation magnetization while retaining a suitable coercive force. Accordingly, high reproduction output can be obtained in a magnetic recording medium employing the magnetic powder.Type: GrantFiled: November 5, 1985Date of Patent: January 13, 1987Assignee: Kabushiki Kaisha ToshibaInventors: Osamu Kubo, Tutomu Nomura, Tadashi Ido, Hirotaka Yokoyama
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Patent number: 4606971Abstract: Disclosed is a magnetic recording medium comprised of a substrate and a layer of magnetic powder coated on a surface of the substrate, characterized in that the magnetic powder is hexagonal crystals having single domain crystalline magnetic anisotropy, particle sizes of 0.01 to 0.3 .mu.m, particle size/thickness ratios of 2.3 to 15 and the tapping packing rate of said magnetic powder is 15% or more.Type: GrantFiled: August 10, 1984Date of Patent: August 19, 1986Assignee: Kabushiki Kaisha ToshibaInventors: Tadashi Ido, Osamu Kubo, Masahiro Fukasawa, Tatsumi Maeda, Tutomu Nomura
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Patent number: 4582623Abstract: Disclosed is a barium ferrite magnetic powder comprising particles characterized by (A) a mean particle size of 0.3 .mu.m or smaller and (B) the presence of Sr, Ca and Si in respective amounts of 0.2 wt. % or less as SrO, 0.15 wt. % or less as CaO, and 0.3 wt. % or less as SiO.sub.2. Also disclosed is a recording medium comprising the barium ferrite magnetic powder.Type: GrantFiled: August 31, 1984Date of Patent: April 15, 1986Assignee: Kabushiki Kaisha ToshibaInventors: Osamu Kubo, Tutomu Nomura, Tadashi Ido
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Patent number: 4578313Abstract: A powder for a magnetic recording medium comprising a plurality of magnetic particles and a coating covering the surfaces of the magnetic particles. The coating is a residue resulting from the thermal decomposition of an organic material. The powder is manufactured by applying one or more organic materials to the surfaces of a plurality of magnetic particles by dispersing the magnetic particles in a solution containing the organic material. The magnetic particles, having the organic material as a coating, are separated from the solution, and the magnetic particles are heated to a temperature at which the organic material decomposes.Type: GrantFiled: September 28, 1983Date of Patent: March 25, 1986Assignee: Tokyo Shibauru Denki Kabushiki KaishaInventors: Takeo Ito, Tadashi Ido, Hajime Takeuchi, Minoru Hashimoto, Tatsumi Maeda, Masashi Awa
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Patent number: 4569775Abstract: A method for preparing a magnetic powder for high density magnetic recording includes melting a mixture containing the fundamental component of a hexagonal ferrite, a substituting component for reducing the coercive force, and boron trioxide as a glass forming substance in predetermined amounts. The resultant molten material is rapidly cooled to obtain an amorphous body which is then heat-treated to produce desired substituted type hexagonal ferrite particles in the glass matrix.Type: GrantFiled: September 8, 1982Date of Patent: February 11, 1986Assignee: Tokyo Shibaura Denki Kabushiki KaishaInventors: Osamu Kubo, Tadashi Ido, Tutomu Nomura, Koichiro Inomata
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Patent number: 4493874Abstract: A hexagonal ferrite magnetic powder for high density magnetic recording, having an improved dispersibility in a binder or paint is obtained by melting a mixture of hexagonal ferrite-forming components and a glass-forming component, and rapidly cooling the resultant molten mixture to obtain an amorphous material. The amorphous material is thermally treated to precipitate fine particles of the hexagonal ferrite therein. The amorphous material containing the precipitated fine particles is dissolved such that the glass-forming component remains on each of said fine particles in an amount of 0.01 to 0.3% by weight based on the weight of the particles.Type: GrantFiled: March 8, 1983Date of Patent: January 15, 1985Assignee: Tokyo Shibaura Denki Kabushiki KaishaInventors: Osamu Kubo, Tadashi Ido, Tutomu Nomura, Tatsumi Maeda
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Patent number: 4425401Abstract: Disclosed is a magnetic recording medium comprising substrate and a resinous composition containing magnetic particles of uniaxially-anisotropic hexagonal crystals having particle diameters of 0.01.about.0.3 .mu.m and coated on said substrate; the ratio of remanent magnetization to saturation magnetization on the magnetization curve corrected to demagnetizing field which is measured in a direction vertical to the surface of the recording medium, ranging from 0.3 to 0.7. This magnetic recording medium requires no orientation treatment for its production.Type: GrantFiled: June 30, 1982Date of Patent: January 10, 1984Assignee: Tokyo Shibaura Denki Kabushiki KaishaInventors: Tadashi Ido, Hirotaka Yokoyama, Moriyasu Wada, Toshihiko Oguchi, Akio Ishizawa, Yoshiyasu Koike
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Patent number: 4407721Abstract: A process for manufacturing a hexagonal ferrite magnetic powder for a magnetic recording medium involves rapidly cooling a molten material of a glass-forming component and a hexagonal ferrite-forming component to obtain glass flakes, heating the glass flakes to precipitate ferrite fine grains, incompletely dissolving the glass flakes with an acid or boiling water, and separating and recovering the fine grains in the presence of a dispersing agent.Type: GrantFiled: September 22, 1981Date of Patent: October 4, 1983Assignee: Tokyo Shibaura Denki Kabushiki KaishaInventors: Yoshiyasu Koike, Osamu Kubo, Tadashi Ido, Masanobu Uwaha
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Patent number: 4341648Abstract: A method for preparing a magnetic powder for high density magnetic recording includes melting a mixture containing the fundamental component of a hexagonal ferrite, a substituting component for reducing the coercive force, and a glass forming material. The resultant molten material is rapidly cooled to obtain an amorphous body which is then heat-treated to produce desired substituted type hexagonal ferrite particles in the glass matrix.Type: GrantFiled: November 3, 1980Date of Patent: July 27, 1982Assignee: Tokyo Shibaura Denki Kabushiki KaishaInventors: Osamu Kubo, Tadashi Ido, Tutomu Nomura, Koichiro Inomata
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Patent number: 4321155Abstract: A piezoelectric oxide material suitable for an ultrasonic probe is provided. The piezoelectric material has the general formula ##EQU1## wherein 0.01.ltoreq.X.ltoreq.0.10 and 0.20.gtoreq.a.ltoreq.0.35, to which is added, as an additive, 0.05 to 2.0% by weight of at least one of MnO, NiO and Fe.sub.2 O.sub.3 based on the total content of the basic composition; the thickness coupling factor (Kt) is 50% or more; the ratio (Kt/Kp) of the thickness coupling factor (Kt) to the planar coupling factor (Kp) is 10 or more.Type: GrantFiled: February 18, 1981Date of Patent: March 23, 1982Assignee: Tokyo Shibaura Denki Kabushiki KaishaInventors: Youhachi Yamashita, Katsunori Yokoyama, Tadashi Ido, Seiichi Yoshida