Patents by Inventor Koichi Shimokawa
Koichi Shimokawa 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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Publication number: 20180268853Abstract: A magnetic disk of is provided, the magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate. In an embodiment, the lubrication layer a film formed by a lubricant having a perfluoropolyether compound A having a perfluoropolyether main chain in the structure and also having a hydroxyl group at the end and a compound C obtained from a reaction between a compound B expressed by: [Chemical formula 1] CF3(—O—C2F4)m-(O—CF2)n-OCF3 [m and n in the formula are natural numbers.] and aluminum oxide.Type: ApplicationFiled: May 11, 2018Publication date: September 20, 2018Inventors: KOICHI SHIMOKAWA, KATSUSHI HAMAKUBO, KAE ITOH
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Patent number: 9984715Abstract: A magnetic disk of is provided, the magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate. In an embodiment, the lubrication layer a film formed by a lubricant having a perfluoropolyether compound A having a perfluoropolyether main chain in the structure and also having a hydroxyl group at the end and a compound C obtained from a reaction between a compound B expressed by: [Chemical formula 1] CF3(—O—C2F4)m-(O—CF2)n-OCF3 [m and n in the formula are natural numbers.] and aluminum oxide.Type: GrantFiled: November 2, 2015Date of Patent: May 29, 2018Assignee: WD Media, LLCInventors: Koichi Shimokawa, Katsushi Hamakubo, Kae Itoh
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Patent number: 9558778Abstract: A lubricant compound is contained in a lubrication layer of a magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, and the lubricant compound contains a component A represented by Chemical formula 1 and a component B represented by Chemical formula 2: wherein X in Chemical formula 1 represents OH wherein X in Chemical formula 2 represents OCH2CH(OH)CH2OH, and the lubricant compound further contains a component C made of a specific compound having a phosphezene ring in the structure thereof.Type: GrantFiled: March 27, 2010Date of Patent: January 31, 2017Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Kota Suzuki, Koichi Shimokawa, Katsushi Hamakubo, Kae Itoh
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Publication number: 20160055874Abstract: A magnetic disk of is provided, the magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate. In an embodiment, the lubrication layer a film formed by a lubricant having a perfluoropolyether compound A having a perfluoropolyether main chain in the structure and also having a hydroxyl group at the end and a compound C obtained from a reaction between a compound B expressed by: [Chemical formula 1] CF3(—O—C2F4)m-(O—CF2)n-OCF3 [m and n in the formula are natural numbers.] and aluminum oxide.Type: ApplicationFiled: November 2, 2015Publication date: February 25, 2016Inventors: Koichi SHIMOKAWA, Katsushi HAMAKUBO, Kae ITOH
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Patent number: 9177586Abstract: A magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate. The lubrication layer is a film formed by a lubricant that contains two types of compounds having a perfluoropolyether main chain in the structure, a molecular weight distribution of the two types in total being within a range of 1 to 1.2. The two types of compounds include a compound a having a hydroxyl group at the end and a compound b having a number average molecular weight smaller than the number average molecular weight of the compound a and not more than 1500. A content of the compound b in the two types of compounds is not more than 10%.Type: GrantFiled: September 30, 2009Date of Patent: November 3, 2015Inventors: Koichi Shimokawa, Katsushi Hamakubo, Kae Itoh
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Patent number: 8999534Abstract: A lubricant for a magnetic disk that is excellent in heat resistance and is suitably used in a magnetic disk to be mounted on a magnetic recording device of a thermally assisted magnetic recording system and a magnetic disk provided with a lubricant layer containing this lubricant. The lubricant for a magnetic disk contains a compound where perfluoropolyether groups each having a perfluoropolyether main chain in its structure and a phosphazene ring at an end are linked to each other through a linking group. The linking group is an aliphatic group or a phosphazene ring. In a magnetic disk having at least a magnetic recording layer, a protective layer, and a lubricant layer on a substrate, the lubricant layer contains the lubricant for a magnetic disk.Type: GrantFiled: June 22, 2010Date of Patent: April 7, 2015Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Koichi Shimokawa, Katsushi Hamakubo
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Patent number: 8999533Abstract: Provided is a magnetic disk comprising a lubricating layer formed of a lubricant. The lubricant constituting the lubricating layer has excellent properties, for example, excellent fluidity, surface energy, and CFT properties. By virtue of the excellent properties, the magnetic disk has a high level of reliability despite a low flying height of a magnetic head due to a recent rapid increase in recording density and a very severe environment resistance requirement due to diversification of applications. The magnetic disk comprises a substrate and at least a magnetic layer, a protective layer, and a lubricating layer provided in that order over the substrate.Type: GrantFiled: March 27, 2009Date of Patent: April 7, 2015Assignee: WD Media (Singapore) Pte. Ltd.Inventor: Koichi Shimokawa
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Patent number: 8920872Abstract: A method of manufacturing a magnetic disk in which at least a magnetic layer, a carbon protective layer, and a lubrication layer are sequentially formed on a substrate is provided. The method comprises forming a film of a lubricant composition on the protective layer, the lubricant comprising a lubricant compound having a perfluoropolyether main chain in the molecular structure and an aromatic group or a phosphazene ring. The method further comprises forming the lubrication layer, and subjecting the magnetic disk to ultraviolet irradiation under a nitrogen gas or an inert gas atmosphere having an oxygen concentration of 5 volume % or less by adjusting an atmospheric temperature to a range of 50 to 180° C.Type: GrantFiled: June 22, 2011Date of Patent: December 30, 2014Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Kae Itoh, Katsushi Hamakubo, Koichi Shimokawa
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Patent number: 8846137Abstract: On manufacturing a magnetic disk having at least a magnetic layer (60), a protective layer (70), and a lubricating layer (80) formed in this order over a substrate (10), the lubricating layer is formed by using a coating solution in which a perfluoropolyether compound having a perfluoropolyether main chain and a hydroxyl group in a structure thereof is dispersed and dissolved in a fluorine-based solvent having a boiling point of 90° C. or more.Type: GrantFiled: February 18, 2010Date of Patent: September 30, 2014Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Koichi Shimokawa, Katsushi Hamakubo, Kae Itoh
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Patent number: 8794196Abstract: A cooling fan includes: a hub; a plurality of cooling vanes provided along an outer circumference of the hub; and an annular connector for connecting the cooling vanes. The hub is provided with a through hole that axially penetrates the hub. A first cover on a case for covering an outward side of the cooling fan is provided with a first outer-air intake. A second cover for partitioning between the cooling fan and a crankcase and for covering an inward side of the cooling fan is provided with a second outer-air intake. With this arrangement, even when one outer-air intake (for instance, the first outer-air intake) adjacent to where the cooling vanes are provided is clogged by a large amount of dust generated during operations, the cooling vanes can breathe from the non-clogged other outer-air intake (for instance, the second outer-air intake) through the through hole, thereby restraining reduction in air flow.Type: GrantFiled: October 6, 2008Date of Patent: August 5, 2014Assignee: Husqvarna Zenoah Co., Ltd.Inventors: Koichi Shimokawa, Kiminobu Sato
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Patent number: 8697262Abstract: A magnetic disk in which at least a magnetic layer, a protective layer, and the lubrication layer are sequentially provided on a substrate, the lubrication layer contains a lubricant compound for a magnetic disk, having a perfluoropolyether main chain in the molecular structure and a structure indicated as follows at a position close to the center of the molecule: -0-CH2—CH(OH)—CH2—CH2—CH(OH)—CH2-0- or -0-CH2—CH(OH)—CH(OH)—CH2-0-.Type: GrantFiled: June 22, 2011Date of Patent: April 15, 2014Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Katsushi Hamakubo, Kae Itoh, Koichi Shimokawa
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Patent number: 8492011Abstract: In a magnetic disk that has at least a magnetic layer, a carbon-based protective layer, and a lubricating layer formed in this order over a substrate, the lubricating layer contains a lubricant compound including a compound which has a perfluoropolyether main chain in a structure thereof, an aromatic group located at a position except each end of a molecule thereof, and a polar group at each end of the molecule.Type: GrantFiled: March 26, 2010Date of Patent: July 23, 2013Assignee: WD Media (Singapore) Pte, Ltd.Inventors: Kae Itoh, Katsushi Hamakubo, Koichi Shimokawa
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Publication number: 20120276417Abstract: A lubricant for a magnetic disk that is excellent in heat resistance and is suitably used in a magnetic disk to be mounted on a magnetic recording device of a thermally assisted magnetic recording system and a magnetic disk provided with a lubricant layer containing this lubricant. The lubricant for a magnetic disk contains a compound where perfluoropolyether groups each having a perfluoropolyether main chain in its structure and a phosphazene ring at an end are linked to each other through a linking group. The linking group is an aliphatic group or a phosphazene ring. In a magnetic disk having at least a magnetic recording layer, a protective layer, and a lubricant layer on a substrate, the lubricant layer contains the lubricant for a magnetic disk.Type: ApplicationFiled: June 22, 2010Publication date: November 1, 2012Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: Koichi Shimokawa, Katsushi Hamakubo
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Publication number: 20120225217Abstract: A method of manufacturing a magnetic disk in which at least a magnetic layer, a carbon protective layer, and a lubrication layer are sequentially formed on a substrate is provided. The method comprises forming a film of a lubricant composition on the protective layer, the lubricant comprising a lubricant compound having a perfluoropolyether main chain in the molecular structure and an aromatic group or a phosphazene ring. The method further comprises forming the lubrication layer, and subjecting the magnetic disk to ultraviolet irradiation under a nitrogen gas or an inert gas atmosphere having an oxygen concentration of 5 volume % or less by adjusting an atmospheric temperature to a range of 50 to 180° C.Type: ApplicationFiled: June 22, 2011Publication date: September 6, 2012Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: KAE ITOH, KATSUSHI HAMAKUBO, KOICHI SHIMOKAWA
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Publication number: 20120148875Abstract: A magnetic disk with which further reduction of magnetic spacing can be realized and which has high reliability under such circumstances of a lower floating amount of a magnetic head involved in the recent rapid increase in recording density and of extremely severe environmental resistance involved in diversification in use applications is provided.Type: ApplicationFiled: June 22, 2011Publication date: June 14, 2012Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: Katsushi Hamakubo, Kae Itoh, Koichi Shimokawa
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Publication number: 20120127599Abstract: A magnetic disk is provided which is excellent in durability of the magnetic disk or particularly in LUL durability and CFT characteristics and has high reliability under a decreased floating amount of the magnetic head accompanying the recent rapid increase in a recording density and extremely severe environmental resistance accompanying diversification of the applications. The magnetic disk of the present invention is a magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate, and the lubrication layer is a film formed by a lubricant that contains two types of compounds having a perfluoropolyether main chain in the structure, a molecular weight distribution of the two types in total being within a range of 1 to 1.Type: ApplicationFiled: September 30, 2009Publication date: May 24, 2012Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: Koichi Shimokawa, Katsushi Hamakubo, Kae Itoh
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Publication number: 20120127601Abstract: A lubricant compound for a magnetic disk is provided which can realize further reduction of the magnetic spacing and moreover, has high reliability under a lower floating amount of the magnetic head involved with the recent rapid increase in the recording density and under extremely severe environmental resistance involved with diversification of the applications. A lubricant compound is contained in a lubrication layer of a magnetic disk in which at least a magnetic layer, a protective layer, and a lubrication layer are sequentially provided on a substrate, and the lubricant compound contains a component A and a component B expressed by the following chemical formula: [Chemical formula] 1 Component A: X=OH Component B: X=OCH2CH(OH)CH2OH and a component C made of a specific compound having a phosphezene ring in the structure thereof.Type: ApplicationFiled: March 27, 2010Publication date: May 24, 2012Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: Kota Suzuki, Koichi Shimokawa, Katsushi Hamakubo, Kae Itoh
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Patent number: 8178480Abstract: A lubricant for magnetic disks which can form a lubricating layer having a reduced thickness while attaining a high coverage and is excellent in heat resistance and adhesion to a protective layer. The lubricant for magnetic disks comprises a perfluoropolyether compound in which the relationship between the number-average molecular weight and the standardized value of the number of hydroxy groups contained in the molecule satisfies the following: the number-average molecular weight is in the range of 1,000-6,000; the standardized value of the number of hydroxy groups contained in the molecule is 180 or higher; and the compound is in a region located below the line connecting the point where the number-average molecular weight is 1,000 and the standardized value of the number of hydroxy groups in the molecule is 400 to the point where the number-average molecular weight is 6,000 and the standardized value of the number of hydroxy groups in the molecule is 1,600.Type: GrantFiled: September 28, 2007Date of Patent: May 15, 2012Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Katsushi Hamakubo, Koichi Shimokawa, Kota Suzuki
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Patent number: 8062778Abstract: In order to obtain a magnetic recording disk that exhibits high reliability even if the flying height of a magnetic head becomes very narrow, a lubricant is specified in terms of both molecular structure and quantitative data. That is, a lubricating layer 14 of the magnetic recording disk 1 is formed by a lubricant which contains perfluoropolyether compounds represented by the following chemical formula (Chemical Formula 1) and which has a first component content of 71.7%, a second component content of 15.7%, a third component content of 11.7%, a fourth component content of 0.3%, and a fifth component content of 0.6%: X—OCH2CF2—(CF2O)m(C2F4O)n—CF2OCH2O—X??(Chemical Formula 1) m, n=9 to 11 first component: X=X1=CH2CH(OH)CH2OH second component: X=X2=CH2CH(OH)CH2OCH2CH(OH)CH2OH third component: X=X3=H fourth component: X=X4=CF3 fifth component: X=X5=CF2Cl.Type: GrantFiled: September 28, 2006Date of Patent: November 22, 2011Assignee: WD Meida (Singapore) Pte. Ltd.Inventors: Kota Suzuki, Koichi Shimokawa
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Patent number: 8012920Abstract: The present invention provides a lubricant for forming a lubricating layer which is useful in preventing fly and stiction and/or corrosion at an extremely small flying height of 10 nm or less, which is prevented from migrating at a high rotational speed of 5400 rpm or more, which has high adhesion, and which is suitable for a load/unload method. A crude lubricant containing at least one perfluoropolyether is degassed and then purified. Alternatively, a liquid crude lubricant containing at least one perfluoropolyether is purified by vaporizing the crude lubricant and then liquefying the vapor of the perfluoropolyether within a distance less than the mean free path of molecules of the perfluoropolyether. A magnetic disk is prepared in such a manner that a carbonaceous protective layer is formed above a substrate and a lubricating layer is formed on the protective layer using of the lubricant. The lubricant contains the perfluoropolyether and has a molecular weight distribution of 1.3 or less.Type: GrantFiled: January 12, 2005Date of Patent: September 6, 2011Assignee: WD Media (Singapore) Pte. Ltd.Inventor: Koichi Shimokawa