Record Medium Patents (Class 360/131)
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Patent number: 4631617Abstract: A magneto-optical recording medium, in which a transparent synthetic resin substance, a light transparent thin film of a simple substance of metal or a metal compound, a dielectric layer, a recording medium layer formed of an amorphous alloy having an easy axis of magnetization in a direction perpendicular to the layer surface and thick enough to reflect light, and a protective film are provided in this order from the light incidence side. The dielectric layer may be provided with an auxiliary recording medium layer formed of the amorphous alloy having an easy axis of magnetization in the direction perpendicular to the layer surface and thin enough to permit the passage therethrough of light.Type: GrantFiled: June 29, 1983Date of Patent: December 23, 1986Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Fujio Tanaka, Nobutake Imamura
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Patent number: 4629653Abstract: A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a magnetic layer containing ferromagnetic particles and a binder, wherein said ferromagnetic particles have a tabular ratio (table diameter/table thickness) of 2 or more, a table diameter of from 0.01 to 10 .mu.m, and a lamination degree of the magnetic particles in the magnetic layer in a cross-section thereof of 2 or more.Type: GrantFiled: December 3, 1984Date of Patent: December 16, 1986Assignee: Fuji Photo Film Co., Ltd.Inventors: Takamitsu Asai, Masaaki Fujiyama, Minoru Kanazawa, Nobuo Aoki
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Patent number: 4628485Abstract: A magneto-optical recording medium comprising: a recording layer of a magnetic thin film low in the Curie temperature or magnetic compensation temperature and high in coersive force and having an easy axis of magnetization in a direction perpendicular to the film surface; a reproducing layer disposed adjacent the recording layer and large in the magnetic Kerr rotation angle and having an easy axis of magnetization in a direction perpendicular to the film surface; and a transparent substrate disposed on the side of incidence of light. In accordance with the present invention, a reflecting metal layer is provided for reflecting light having entered from the side of the transparent substrate and passed through the recording layer and the reproducing layer. A dielectric layer may be further disposed at least on one side of the transparent substrate or the reflecting metal layer with respect to the recording layer and the reproducing layer.Type: GrantFiled: July 17, 1984Date of Patent: December 9, 1986Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Fujio Tanaka, Yasuyuki Nagao, Nobutake Imamura
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Patent number: 4626469Abstract: A magnetic recording material, which comprises a magnetic layer coated on a non-magnetic support is disclosed. The magnetic layer contains both carbon black fine powder having a mean primary grain size of less than 10 m.mu. and carbon black coarse powder having a mean primary grain size in the range of 50 to 120 m.mu. in a mixing ratio ranging from 95/5 to 5/95. The material is improved in both RF output and audio output.Type: GrantFiled: June 17, 1983Date of Patent: December 2, 1986Assignee: Fuji Photo Film Co., Ltd.Inventors: Nobutaka Yamaguchi, Kenichi Masuyama, Shinobu Iida, Masaaki Fujiyama
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Patent number: 4619861Abstract: Magnetic powders have a thin film of a nitrogen- or sulfur-containing organic polymer synthesized on the individual particles by plasma polymerization. The film is not more than 100 .ANG. in thickness.Type: GrantFiled: July 19, 1985Date of Patent: October 28, 1986Assignee: TDK CorporationInventors: Masatoshi Nakayama, Haruyuki Morita, Yuichi Kubota
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Patent number: 4617601Abstract: A magneto-optical recording medium having a magnetic film layer on one flat surface of the recording medium, which magnetic film layer is magnetizable in the direction normal to the surface of the medium; and guide tracks on the other side opposite to the magnetic film layer.Type: GrantFiled: May 3, 1983Date of Patent: October 14, 1986Assignee: Ricoh Company, Ltd.Inventor: Motoharu Tanaka
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Patent number: 4615944Abstract: A magneto optical thin film recording medium is disclosed having very high carrier-to-noise ratios and high rotation angles. A transmission electron microscope photomicrograph (at 200,000.times.) of one such medium is shown in FIG. 1. These are multi-phase amorphous materials having magnetic anisotropy perpendicular to the plane of the thin film. They are produced in a triode vacuum sputtering process at vacuums in the range of 4.times.10.sup.-3 to 6.times.10.sup.-4 Torr. By adjusting process parameters such as substrate temperature, anode bias and deposition rate, the properties of the thin film can be altered.Type: GrantFiled: April 12, 1984Date of Patent: October 7, 1986Assignee: Minnesota Mining and Manufacturing CompanyInventor: Richard N. Gardner
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Patent number: 4609962Abstract: A metal thin film type magnetic recording medium having an improved weather resistance is disclosed, which comprises a non-magnetic support base having provided thereon a ferromagnetic metal thin film comprised of column-shaped clusters of ferromagnetic particle having longitudinal axes inclined to the surface plane of the support base and a layer of a chromium compound such as Cr and Cr.sub.2 O.sub.3 covering the surfaces of the column-shaped clusters.Type: GrantFiled: April 4, 1984Date of Patent: September 2, 1986Assignee: Fuji Photo Film Co., Ltd.Inventors: Yoshihiro Arai, Akira Nahara, Makoto Nagao, Kiyotaka Fukino
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Patent number: 4596740Abstract: The present invention relates to a magnetooptic recording medium for recording and reproducing information using laser beams and is a magnetooptic recording carrier which forms on a plastic substrate, a polymer layer having a good bondability with the plastic substrate and forming a rare earth-transition metal amorphous layer on the polymer layer.Type: GrantFiled: October 5, 1984Date of Patent: June 24, 1986Assignee: Daicel Chemical Industries, Ltd.Inventor: Nagayoshi Tsukane
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Patent number: 4593336Abstract: A permanently structured magnetic recording tape includes a pattern of first and second regions of acicular iron oxide particles, the first `A` regions being orientated at 22.5.degree. (clockwise) to the tapes axis and the second `B` regions being orientated at 67.5.degree. (clockwise) to the tape axis. A permanent magnet applies a developing field at 45.degree. (anti-clockwise) to the tape axis such that, at the transition in orientation direction, the normal components of remanence in `A` and `B` regions are in opposite directions, thereby increasing pole strength at the transitions compared with longitudinal development, and enhancing the output signal at the magnetoresistive read-out transducer.A second magnetoresistive transducer senses fluctuations in magnetic polarity at the tape edge to verify whether the medium is genuine.Type: GrantFiled: May 17, 1983Date of Patent: June 3, 1986Assignee: Emi LimitedInventor: David J. Sansom
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Patent number: 4579777Abstract: An opto-magnetic recording medium comprises a light-transmitting substrate, a first protective layer comprising a metal film provided in contact with the substrate and transmitting therethrough almost all of a light entering through the substrate, a second protective layer formed of a dielectric material provided on the first protective layer, and a magnetic recording layer provided on the second protective layer and having information recorded or reproduced thereon by the light transmitted through the substrate and the first and second protective layers.Type: GrantFiled: July 2, 1985Date of Patent: April 1, 1986Assignee: Canon Kabushiki KaishaInventors: Kazuoki Honguu, Mitsuharu Sawamura, Kazuhiko Kikuchi
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Patent number: 4578322Abstract: A recording medium is provided which comprises (a) a first recording layer; (b) a second recording layer provided in contiguity to the first recording layer; and (c) a separation layer for spatially separating the first and second recording layer. The first recording layer has a sufficient film thickness not to permit the recording to be effected on the second recording layer, while the recording operation is performed on the first recording layer, and the recording operation is effected on the second recording layer at positions corresponding to defective portions in the first recording layer.Type: GrantFiled: June 14, 1985Date of Patent: March 25, 1986Assignee: Canon Kabushiki KaishaInventors: Mitsuharu Sawamura, Susumu Ito, Masaaki Matsushima, Hiroyoshi Kishi, Eizo Sasamori, Satoshi Yoshihara, Shigeharu Iijima, Katsuhiko Takano
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Patent number: 4576876Abstract: A magnetic recording medium comprising a substrate, an underlayer provided on the substrate and having a high permeability magnetic film and a relative permeability in all directions in the film surface of not less than 800, and a recording medium layer provided on the underlayer and having a perpendicular anisotropy. The recording and reproduction characteristics of this magnetic recording medium do not vary even when the direction of movement thereof with respect to a magnetic head varies. When it is applied to a magnetic disc, preferable results can be obtained.Type: GrantFiled: September 19, 1984Date of Patent: March 18, 1986Assignees: Hitachi, Ltd, Hitachi Maxell, Ltd.Inventors: Kazuo Shiiki, Yoshihiro Shiroishi, Osamu Kitakami, Yasutaro Uesaka
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Patent number: 4569881Abstract: A multi-layer magneto optical thin film recording medium is disclosed having very high carrier-to-noise ratios (at least 47 decibels) and high rotation angles. A transmission electron microscope photomicrograph (at 200,000 X) of one such medium is shown in FIG. 1. The magneto optic layer is a multi-phase amorphous material having magnetic anisotropy perpendicular to the plane of the thin film produced in a triode vacuum sputtering process at vacuums in the range of 4.times.10.sup.-3 to 6.times.10.sup.-4 Torr. Various transparent layers, such as dielectric intermediate and anti-reflective layers and a protective covering layer, are combined with the magneto optic layer and a reflective surface to yield media having enhanced carrier-to-noise ratio and magnetic optic angle of rotation.Type: GrantFiled: April 12, 1984Date of Patent: February 11, 1986Assignee: Minnesota Mining and Manufacturing CompanyInventors: Robert P. Freese, Leslie H. Johnson, Thomas A. Rinehart, Richard N. Gardner
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Patent number: 4563397Abstract: Aluminum or an aluminum alloy on the surface of which an anodic oxide film comprising a porous layer and a barrier layer having micropores in the porous layer has been formed by a primary anodic oxidation treatment is subjected to a secondary anodic oxidation treatment and an immersion treatment so as to enlarge the pore diameter of the micropores, to make the cross-sectional profile of the micropores circular, and to make the thickness of the barrier layer and thus, the length of the micropores uniform, and subjecting the so treated aluminum or aluminum alloy to an electrolytic deposition treatment in an electrolytic bath containing a magnetic substance so as to uniformly allow a large amount of the magnetic substance to be deposited in the enlarged, uniform micropores, thereby obtaining a magnetic recording material having improved magnetic intensity and magnetic characteristics.Type: GrantFiled: September 11, 1984Date of Patent: January 7, 1986Assignee: Pilot Man-Nen-Hitsu Kabushiki KaishaInventors: Ikuo Ishiguro, Hiroyuki Nagao
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Patent number: 4559573Abstract: A magneto-optical recording medium having an easy axis of magnetization in a direction perpendicular to the film surface, characterized in that a readout medium layer, a reflection layer and a recording medium layer are sequentially disposed in a direction of the incidence of a reading-out light, thereby to increase a reproduced output.Type: GrantFiled: November 9, 1982Date of Patent: December 17, 1985Assignee: Kokusai Denshin Denwa Kabushiki KaishaInventors: Shinsuke Tanaka, Fujio Tanaka, Yasuyuki Nagao, Nobutake Imamura, Chuichi Ota
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Patent number: 4556291Abstract: A magneto-optic storage media which utilizes two layers or films of magnetic material, with the magneto-optic hysteresis loop of one of the films being of a sense opposite to the sense of the magneto-optic hysteresis loop of the other film. The media permits the Farraday effect polarization rotations produced by one of the magnetic films to be in phase with Kerr effect polarization rotations produced by the other of the magnetic films, such that additive mode conversion is provided from different portions of the media whereby the detected signal has an increased signal-to-noise ratio.Type: GrantFiled: August 8, 1983Date of Patent: December 3, 1985Assignee: Xerox CorporationInventor: Tu Chen
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Patent number: 4554606Abstract: A magnetic recording medium having two magnetic layers, which comprises an upper magnetic layer and a lower magnetic layer, said lower magnetic layer having a coercive force of at least 100 oersteds, preferably 100 to 500 oersteds, lower than that of the upper magnetic layer, the thickness of the upper and lower magnetic layers being in the ratio of the thickness of the upper magnetic layer to that of the lower magnetic layer of 1/1 to 1/9, and the total coercive force of the upper and lower magnetic layers being 1,000 oersteds or more. The magnetic recording medium has excellent sensitivity and frequency characteristics at low and high frequency bands with less noise.Type: GrantFiled: October 12, 1982Date of Patent: November 19, 1985Assignee: Hitachi Maxell, Ltd.Inventors: Takato Karashima, Hiroshi Zaitsu
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Patent number: 4551778Abstract: A magnetic recording medium and a process for producing it is disclosed. The medium is comprised of a non-magnetic flexible support base and a magnetic layer formed on a surface of the support base. The magnetic layer is preferably in the form of a thin, ferromagnetic metal film formed by vapor deposition. An overcoat layer of a fluorine-containing organic material is formed directly on the magnetic layer. The fluorine content of the overcoat layer continuously and gradually decreases in the direction toward the magnetic layer. Accordingly, high fluorine content near the surface of the overcoat layer provides improved smoothness near the surface whereas the lower fluorine content near the interface of the overcoat with the magnetic layer allows for strong adhesion between the overcoat and the underlying magnetic layer substrate.Type: GrantFiled: August 2, 1983Date of Patent: November 5, 1985Assignee: Fuji Photo Film Co., Ltd.Inventors: Yoshihiro Arai, Akira Nahara
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Patent number: 4468436Abstract: A magnetic recording material and a process for producing it are disclosed. The material is excellent in abrasion resistance and has good electric characteristics. The material is obtained by coating on a support a subbing layer having a compound which contains a compound having an unsaturated bond polymerizable upon irradiation with electron beams. Upon the subbing layer is coated a ferromagnetic layer which contains a compound having an unsaturated bond polymerizable upon irradiation with electron beams, an organic solvent capable of dissolving the compound, and a ferromagnetic fine powder. The material is then subjected to an electron-beam irradiating processing to result in the hardening of the subbing and ferromagnetic layers through polymerization.Type: GrantFiled: December 23, 1982Date of Patent: August 28, 1984Assignee: Fuji Photo Film Co., Ltd.Inventors: Tsutomu Okita, Kiritani Masataka
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Patent number: 4467383Abstract: Disclosed is a new magnetic storage medium including a layer of amorphous material typically GdDyFe whose Curie recording point (e.g. 120.degree. C.) is lower than its crystallization point (e.g. 350.degree. C.) to enable crystallization to cause variations in its optical properties such as transmittance or reflectivity for thermomagnetic writing. Reversible recordings are set up on the amorphous material layer by a thermomagnetic writing technique, for example Curie point writing, while unchangeable or permanent recordings are set up on the amorphous material layer through laser-activated crystallization of the amorphous material layer.Type: GrantFiled: February 23, 1981Date of Patent: August 21, 1984Assignee: Sharp Kabushiki KaishaInventors: Kenji Ohta, Toshihisa Deguchi, Akira Takahashi
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Patent number: 4463034Abstract: Heat-sensitive magnetic transfer element for printing a magnetic image to be recognized by a magnetic ink character reader (MICR), comprising a heat-resisting foundation and a heat-sensitive transferring layer provided on the foundation, the transferring layer which includes a ferromagnetic substance powder and has a melting point of 50.degree. to 120.degree. C. being readily melted and transferred on a receiving paper in the form of magnetic image by a thermal printer.Type: GrantFiled: March 15, 1982Date of Patent: July 31, 1984Assignees: Nippon Telegraph & Telephone Public Corp., Fuji Kagakushi Kogyo Co., Ltd.Inventors: Yukio Tokunaga, Yasuhisa Ikeda, Tadao Seto, Yoshikazu Shimazaki
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Patent number: 4439795Abstract: A magnetic recording medium is described having formed on a non-magnetic base at least two magnetic layers, each of the magnetic layers comprising ferromagnetic particles dispersed in a binder, wherein the ferromagnetic particles in the outermost layer have an average length of 0.3.mu. or less and a length to width ratio of greater than 1/1 but not greater than 3/1, and the ferromagnetic particles in an underlying layer have a length to width ratio of more than 3/1.Type: GrantFiled: December 9, 1981Date of Patent: March 27, 1984Assignee: Fuji Photo Film Co., Ltd.Inventors: Tatsuji Kitamoto, Goro Akashi
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Patent number: 4439796Abstract: A magnetic recording medium is described having formed on a non-magnetic base at least two magnetic layers, each of the magnetic layers comprising ferromagnetic particles dispersed in a binder, wherein the ferromagnetic particles in the outermost magnetic layer are substantially cubic particles and have a side length of 0.3.mu. or less, and the ferromagnetic particles in an underlying magnetic layer are acicular particles.Type: GrantFiled: December 9, 1981Date of Patent: March 27, 1984Assignee: Fuji Photo Film Co., Ltd.Inventors: Tatsuji Kitamoto, Goro Akashi
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Patent number: 4423452Abstract: A magnetic recording medium comprises a substrate coated with a magnetic layer comprising a magnetic powder and a fine titanium oxide powder having a particle diameter of at least 0.4.mu. and at least one other fine hard non-magnetic powder.Type: GrantFiled: July 8, 1981Date of Patent: December 27, 1983Assignee: TDK Electronics Co., Ltd.Inventors: Norifumi Kajimoto, Yoshio Kawakami, Kinji Sasaki
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Patent number: 4423453Abstract: A magnetic recording medium having two coated magnetic layers of a first magnetic layer and a second magnetic layer on a non-magnetic substrate. The first magnetic layer has a coercive force of 400 to 590 Oe and a thickness of 2.1 to 2.8.mu. and said second magnetic layer has a coercive force of 590 to 800 Oe and a thickness of at least 2.1.mu..Type: GrantFiled: July 13, 1981Date of Patent: December 27, 1983Assignee: TDK Electronics Co., Ltd.Inventors: Hiroshi Kawahara, Hitoshi Azegami, Eiji Horigome
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Patent number: 4423454Abstract: A magnetic recording disk comprising a non-magnetic substrate and two or more firmly adhering magnetizable layers applied to one or both sides thereof, the layer located directly on the substrate being magnetically isotropic, while the second layer and any additional layers exhibit orientation of the anisotropic magnetic particles parallel to the substrate and to the envisaged recording direction.Type: GrantFiled: June 26, 1980Date of Patent: December 27, 1983Assignee: BASF AktiengesellschaftInventors: Peter Felleisen, Dieter Mayer, Eberhard Koester, Friedrich Domas, Paul Deigner
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Patent number: 4417290Abstract: A multi-layer magneto-optical recording medium is constructed by placing a transparent protective film upon a magneto-optical recording medium wherein the easy axis of magnetization is provided perpendicular to the film surface so as to make the direction of magnetization perpendicular thereto to take a binary code depending on whether the vertical direction thereof is upward or downward, and further by placing a metal film, of which melting point is lower than either said magneto-optical recording medium and said transparent protective film, upon said transparent protective film.The metal film is evaporated by a laser beam irradiated thereon in a manner to leave a portion thereof not evaporated to become a tracking guide, whereby reproducing a magneto-optical record free of disturbance on linear polarization.The metal film can be perforated to form pits by irradiation of a laser beam.Type: GrantFiled: August 19, 1981Date of Patent: November 22, 1983Assignee: Kokusai Denshindenwa Co., Ltd.Inventors: Shinsuke Tanaka, Nobutake Imamura, Chuichi Ota
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Patent number: 4416968Abstract: A dry-printing process which employs a photopolymer film and two toners, one for generating a master and a second for image transfer.Type: GrantFiled: September 9, 1982Date of Patent: November 22, 1983Assignee: E. I. Du Pont de Nemours & Co.Inventor: Robert P. Held
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Patent number: 4412264Abstract: Disclosed is a magneto-optic recording medium to which magnetic Kerr effect is applied and characterized by the tracking guide on an even surface free from disorder of linear polarization. Since the tracking guide may be any type if it has a different reflection characteristic from that of the memory area viewing from magneto-optic standpoint, the tracking guide can be produced by a thermal treatment for changing the magnetic property of a part of a thin film with its magnetization easy axis in the direction perpendicular to the film surface. As no difference exists between the memory area and the guide area other than their magnetic properties, they are on the same plane and have no unevenness between their surfaces. Where, the guide area is assumed to have such magnetic property as the magnetization easy axis is parallel to the film surface, or it is perpendicular to the film surface but has no rectangular hysterisis.Type: GrantFiled: October 17, 1980Date of Patent: October 25, 1983Assignee: Kokusai Denshin Denwa Co., Ltd.Inventors: Nobutake Imamura, Chuichi Ota
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Patent number: 4408242Abstract: A magnetically recorded program member for an embroidering machine which includes a plurality of data recording blocks containing control data for at least one of thread change, frame change and applying an applique cloths, the data recording blocks being arranged with non-recorded blocks interposed therebetween, and voice recording blocks having records based on the control data.Type: GrantFiled: September 16, 1981Date of Patent: October 4, 1983Assignee: Aisin Seiki Kabushiki KaishaInventors: Koji Nishida, Taneichi Kawai
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Patent number: 4380779Abstract: A magnetic recording method for recording a multiplex signal having two different frequency signals. A magnetic recording medium is used having a magnetic layer with a thickness which is smaller than a recorded wavelength of each of said two signals. The signal of a higher frequency is recorded at a current which is more than 2dB larger than the lower limit of the recording current with which a reproduced output level is saturated, and which is smaller than a current with which the reproduced output level is reduced by 1dB beyond said saturated condition. The signal of a lower frequency is recorded at a current which is smaller than one half of that of the signal of a higher frequency.Type: GrantFiled: March 23, 1981Date of Patent: April 19, 1983Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Sadafumi Kitamura, Hiroshi Taniguchi
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Patent number: 4363038Abstract: A system for contact duplication is disclosed wherein anhysteretic magnetization of a copy medium occurs using an anisotropic master medium wherein the two media are held in surface contact and an AC bias magnetic field is applied along the hard axis of the master media.Type: GrantFiled: July 14, 1980Date of Patent: December 7, 1982Assignee: Minnesota Mining and Manufacturing CompanyInventor: Richard E. Fayling
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Patent number: 4351010Abstract: A magnetic recording medium comprises a substrate of a non-magnetic material and a magnetic recording layer of a magnetic material provided thereon having an axis of easy magnetization vertical to the magnetic recording layer. The magnetic recording medium has a magnetic flux converging element of high permeability material provided between the substrate and the magnetic recording layer or on the exposed surface of the substrate. The magnetic flux converging element converges a magnetic flux diverging from a magnetic head which is located above the magnetic recording medium.Type: GrantFiled: March 14, 1980Date of Patent: September 21, 1982Assignee: Fuji Photo Film Co., Ltd.Inventor: Yoshihiro Arai
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Patent number: 4318141Abstract: A single-gap transducer simultaneously senses recorded control or servo signals and record data signals. A magnetic medium used with this invention is preferably a single layer magnetic medium. The head gap length and pole-tip face length allow different portions of the pole pieces in a magnetic transducer to be utilized during the simultaneous read and record operations. The servo signals are preferably deep and hard recorded into the layer whereas the data signals are preferably pulse width limited and recorded adjacent the surface portion of the magnetic layer.Type: GrantFiled: December 7, 1979Date of Patent: March 2, 1982Assignee: International Business Machines Corp.Inventor: Munro K. Haynes
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Patent number: 4313140Abstract: A single gap transducer simultaneously senses recorded control or servo signals and records data signals. A magnetic medium used with this invention is preferably a single coating magnetic medium. During recording, the recording signal is appropriately subtracted from the readback signal for removing write signal effects on the readback signal. The servo signals are preferably deeply recorded into the magnetic coating whereas the data signals are preferably recorded in an outer surface portion of the magnetic coating.Type: GrantFiled: December 7, 1979Date of Patent: January 26, 1982Assignee: International Business Machines CorporationInventor: Steven D. Keidl
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Patent number: 4302790Abstract: Rather than the prior art practice of magnetically recording with a relatively long record gap, the disclosed invention teaches the use of a magnetic record gap length of less than 15.mu.". Such a record gap length provides improved performance in a variety of recorders.Type: GrantFiled: April 11, 1979Date of Patent: November 24, 1981Assignee: Eastman Kodak CompanyInventor: James U. Lemke
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Patent number: 4291100Abstract: A magnetic recording medium comprises a substrate coated with a magnetic layer wherein a magnetic powder is orientated in a binder and a polyoxyethylenesorbitane higher fatty acid ester surfactant.Type: GrantFiled: June 20, 1980Date of Patent: September 22, 1981Assignee: TDK Electronics Co., Ltd.Inventors: Eiji Horigome, Hiroshi Ota, Hitoshi Azegami
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Patent number: 4287544Abstract: A carrier for magnetic data recorded therein by perpendicular recording comprises a non-magnetic substrate having at least one substantially plane surface provided with a magnetic data layer of an anisotropic magnetic material having its axis of easy magnetization perpendicular to the said plane surface, and includes an additional layer of an anisotropic magnetic material whose axis of hard magnetization is parallel to the said plane surface. An intermediate non-magnetic, insulative coupling layer may be provided to maximize magneto-static coupling between the layers while minimizing energy exchanges therebetween. A further non-magnetic sub-layer may be provided directly on the plane surface of the substrate to assure good adhesion of the additional layer to the substrate and isolation thereof from the magnetic layer.Type: GrantFiled: January 2, 1979Date of Patent: September 1, 1981Assignee: Compagnie Internationale pour l'Informatique CII-Honeywell Bull (Societe Anonyme)Inventor: Jean-Pierre Lazzari
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Patent number: 4277809Abstract: Apparatus is disclosed for recording magnetic impulses on a selectively magnetizable medium with such impulses being recorded with their axes of magnetization substantially perpendicular to the surface of the medium utilizing a recording medium having a high magnetic permeability backing layer and an overlying coating of magnetic material having uniaxial anisotropy substantially perpendicular to the surface of the backing layer, and using a unitary magnetic head for both recording and playback with such head positioned adjacent to one side of the recording medium.Type: GrantFiled: September 26, 1979Date of Patent: July 7, 1981Assignee: Memorex CorporationInventors: Robert D. Fisher, Eric R. Katz
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Patent number: 4277806Abstract: A magnetic recording which is useful as a mirror image duplication video tape master is made from another magnetic recording by anhysteretic transfer at a temperature at which the coercive force of the master is much less than the coercive force of the other recording. Preferably, the magnetic recording layer of the master comprises fine particles of a manganese bismuth alloy, the coercivity of which decreases with decreasing temperature, and the other record comprises a magnetic recording layer having a coercivity which increases with decreasing temperature. The master record may subsequently be used to duplicate copies of the recording by anhysteretic transfer to a copy record having a coercive force which, at the temperature at which the transfer is made (typically room temperature), is substantially lower than the coercive force of the master.Type: GrantFiled: May 14, 1979Date of Patent: July 7, 1981Assignee: Eastman Technology, Inc.Inventors: Frederick J. Jeffers, Richard J. McClure
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Patent number: 4275113Abstract: Magnetic recording medium comprising a support or carrier sheet and a magnetic layer formed on one side of the support, wherein there is provided between the support and the magnetic layer at least one intermediate layer of resinous polymeric material including particles of carbon black having large specific surface area and high oil absorption so that electrification of the recording medium can be prevented with good adhesiveness of the magnetic layer to the support.Type: GrantFiled: October 17, 1979Date of Patent: June 23, 1981Assignee: Hitachi Maxell, Ltd.Inventors: Osamu Saito, Jozo Shimizu, Hiroshi Zaitsu
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Patent number: 4271442Abstract: A plane magnetic recording medium comprises a data track traced by a magnetic head wherein said data track is initiallized to have each width smaller than a width of the trace of the magnetic head whereby modulation in its reproducing output can be minimized.Type: GrantFiled: March 29, 1979Date of Patent: June 2, 1981Assignee: TDK Electronics Co., Ltd.Inventor: Yoshio Mikame
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Patent number: 4246316Abstract: This invention relates to a magnetic recording medium comprising a non-magnetic support and magnetic layer provided thereon containing a ferromagnetic metal powder, the magnetic layer having a multilyaer structure consisting of a lower layer containing acicular grains obtained by dry process reduction and an upper layer containing chain-like grains obtained by wet process reduction, the upper layer being provided on the lower layer. This magnetic recording medium is particularly suitable for high density recording.Type: GrantFiled: March 17, 1978Date of Patent: January 20, 1981Assignee: Fuji Photo Film Co., Ltd.Inventors: Masashi Aonuma, Yasuo Tamai
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Patent number: 4239959Abstract: A uniformly distributed magnetic recording medium is carried on or in an initially fluidizable support. During or after magnetically writing information upon the medium, the support is changed to a fluidized state, sufficient to permit some physical translational movement of the medium in localized areas corresponding in pattern to characteristic magnetic non-uniformities caused in medium by the magnetic writing. The support is then set or otherwise converted to a state in which such movement is no longer possible. Thereafter, even if the medium is degaussed, the now set non-uniformities in physical distribution of the recording medium, will permit the information that had been magnetically written, to continue to be read e.g. by magnetic analysis of the medium.Type: GrantFiled: March 23, 1977Date of Patent: December 16, 1980Assignee: General Kinetics IncorporatedInventor: Robert P. Gutterman
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Patent number: 4238809Abstract: A servo track apparatus comprising at least one unit pattern area including 2n (n=2, 3, 4, . . . ) servo tracks T.sub.i (i=0, 1, . . . 2n-1) and 2n.sup.2 flux transitions R.sub.jk (j=0, 1, . . . 2n-1; k=0, 1, . . . n-1). The tracks and flux transitions satisfy a condition TT requiring that track T.sub.p be adjacent to track T.sub.p+1 ; a condition TR requiring that transition R.sub.pq occur on track T.sub.p+q (mod 2n); a condition RR requiring that transitions R.sub.pq and R.sub.pr (r.noteq.q) have the same polarity and occur at the same position; and a condition RR requiring that transitions R.sub.pr and R.sub.qr (q.noteq.p) occur at different positions.Type: GrantFiled: March 5, 1979Date of Patent: December 9, 1980Assignee: Tokyo Shibaura Denki Kabushiki KaishaInventors: Masao Fujiki, Hiromi Hamaoka, Toshiaki Hattori
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Patent number: 4237506Abstract: An improved magnetic recording member of the disc type, the article of the invention is polymodal wherein one mode is formed of a first population of magnetic particles which have a coercivity differing by at least 200 oersteds from the coercivity of particles in another mode. These latter particles are, preferably, metallic magnetic particles oriented in a vertical direction and are in a thin layer over said first population of magnetic particles. This combination overcomes existing limitations on (a) disc products, and (b) the preferred metallic particles heretofore known.Type: GrantFiled: April 3, 1978Date of Patent: December 2, 1980Assignee: Graham Magnetics Inc.Inventor: William A. Manly
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Patent number: 4210946Abstract: A magnetic recording medium suitable for use in a recording system employing a magnetic recording transducer or head of the single-pole type which operates in a perpendicular magnetization mode comprises a non-magnetic base supporting a layer of low coercive force material formed on the base and which underlies a magnetic recording layer. The magnetic recording layer which faces the magnetic recording transducer or head is formed of an alloy composed mainly of chromium and cobalt and has an easy axis of magnetization perpendicular to the surface of the magnetic recording layer, with the thickness of the latter being no greater than 3.0 microns. The low coercive force material layer has a coercive force no greater than 1/5 of the coercive force of the magnetic recording layer, and the thickness of the low coercive force layer is greater than 0.1 microns.Type: GrantFiled: September 19, 1978Date of Patent: July 1, 1980Assignees: Sony Corporation, Fujitsu Limited, Shun-Ichi IwasakiInventors: Shun-Ichi Iwasaki, Yoshihisa Nakamura
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Patent number: 4202932Abstract: A magnetic recording medium comprising a thin film of magnetic material disposed upon a non-magnetic substrate wherein the magnetic material is an alloy of cobalt with a second constituent which may be rhenium, ruthenium or osmium. The magnetic material will have a coercive force of up to 800 Oe and a squareness ratio of up to 98%.Type: GrantFiled: October 16, 1978Date of Patent: May 13, 1980Assignee: Xerox CorporationInventors: Tu Chen, George B. Charlan
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Patent number: 4172171Abstract: 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: GrantFiled: November 4, 1977Date of Patent: October 23, 1979Assignee: Fuji Photo Film Co., Ltd.Inventors: Masaaki Suzuki, Ryuji Shirahata