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Koichi Shimokawa

Koichi Shimokawa, Shinjuku-Ku JP

Patent application numberDescriptionPublished
20100028721LUBRICANT FOR MAGNETIC DISK, PROCESS FOR PRODUCING THE SAME, AND MAGNETIC DISK - 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. The compound has at least one hydroxy group around the center of the molecular chain.02-04-2010
20100232065MAGNETIC DISK AND METHOD OF MANUFACTURING THE SAME - A magnetic disc is provided with a magnetic layer, a protection layer and a lubrication layer in this order on a substrate. After successively forming the magnetic layer and the protection layer on the substrate, the protection layer is exposed to plasma under normal pressure, then, the lubrication layer is formed on the protection layer. The plasma is generated in at least one kind of gas selected from among nitrogen gas, argon gas, oxygen gas, and fluorine hydrocarbon gas. The protection layer is a hydrogenated carbon protection layer.09-16-2010
20100304186MAGNETIC DISK AND METHOD OF MANUFACTURING THE SAME - 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. The lubricating layer is formed of a lubricant that is a mixture of a specific perfluoropolyether lubricant with a lubricant formed of a compound comprising perfluoropolyether groups having a perfluoropolyether main chain in the structure thereof and having a hydroxyl group at the end thereof, the perfluoropolyether groups being bonded to each other through a divalent linking group having at least two hydroxyl groups in the structure thereof.12-02-2010

Koichi Shimokawa, Tokyo JP

Patent application numberDescriptionPublished
20090023017MAGNETIC DISK - Disclosed is a magnetic disk which has a lubricant layer with excellent heat resistance and high adhesiveness and is free from fly-stiction failure or corrosion failure even at an extremely low flying height of 01-22-2009
20090136784MAGNETIC RECORDING DISK AND METHOD FOR MANUFACTURE THEREOF - In a magnetic recording disk 05-28-2009
20090155517Magnetic Recording Disk and Method for Manufacture Thereof - 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 06-18-2009
20100209601METHOD OF MANUFACTURING A MAGNETIC DISK - On manufacturing a magnetic disk having at least a magnetic layer (08-19-2010
20100246064LUBRICANT COMPOUND FOR A MAGNETIC DISK, MAGNETIC DISK, AND METHOD OF MANUFACTURING THE SAME - In a magnetic disk 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.09-30-2010

Patent applications by Koichi Shimokawa, Tokyo JP

Koichi Shimokawa, Kawagoe-Shi JP

Patent application numberDescriptionPublished
20100083511CHAIN SAW - 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.04-08-2010
20100083512CHAIN SAW - A muffler includes a muffler body disposed on a lower portion of an engine and a passage that extends upward from the muffler body and is opened in an upper front portion of a chain saw body. Thus, exhaust gas can be discharged forward from the chain saw body, so that exhaust sounds can be dispersed forward. Consequently, the exhaust sounds propagated to an operator can be reduced and therefore a work environment can be improved. Also, since exhaust gas is discharged after the exhaust gas passes through a long passage extending upward from the muffler body, the exhaust gas can be cooled down. Accordingly, in the chain saw body typically covered with a synthetic-resin case in which exhaust outlets are formed on positions corresponding to outlets of the passage, peripheries of the exhaust outlets can be prevented from being discolored by heat of exhaust gas.04-08-2010