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公开(公告)号：US20190304496A1
公开(公告)日：2019-10-03
申请号：US16260027
申请日：2019-01-28
Applicant: FUJIFILM CORPORATION
Inventor： Takashi FUJIMOTO
Abstract: Provided are a magnetic recording medium including: a non-magnetic support; and a magnetic layer which is provided on at least one surface of the non-magnetic support and includes particles of epsilon type iron oxide-based compound, and a binding agent, in which a contact angle measured regarding a surface of the magnetic layer is equal to or greater than 30.0° and smaller than 45.0° with respect to 1-bromonaphthalene and 80.0° to 95.0° with respect to water, a manufacturing method of particles of an epsilon iron oxide-based compound, and a manufacturing method of a magnetic recording medium.
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12.发明公开公开(公告)号：US20230290376A1
公开(公告)日：2023-09-14
申请号：US18182723
申请日：2023-03-13
Applicant: FUJIFILM Corporation
Inventor： Takashi FUJIMOTO , Eiki OZAWA
CPC classification number: G11B5/70642 , G11B5/712 , G11B5/702
Abstract: The magnetic recording medium includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. A magnetic tape cartridge and a magnetic recording and reproducing device include the magnetic recording medium. The ferromagnetic powder is an ε-iron oxide powder, and a ferromagnetic powder filling rate of a magnetic layer surface obtained by observing a surface of the magnetic layer with a scanning electron microscope is 0.40 or more and 0.60 or less.
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公开(公告)号：US20200071188A1
公开(公告)日：2020-03-05
申请号：US16548307
申请日：2019-08-22
Applicant: FUJIFILM Corporation
Inventor： Takashi FUJIMOTO
Abstract: Provided is a powder of a β-iron oxyhydroxide-based compound that is a group of particles of a ρ3-iron oxyhydroxide-based compound represented by Formula (1) below; in which a surface of the particles of the β-iron oxyhydroxide-based compound is modified with a surface modifier; in which, in a case where the powder is dispersed in water to be made into a sol, a zeta potential of the powder is equal to or higher than +5 mV at pH 10; and β-AaFe1-aOOH (1) in which, in Formula (1), A represents at least one metallic element other than Fe, and a represents a number that satisfies a relationship of 0≤a
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公开(公告)号：US20180151277A1
公开(公告)日：2018-05-31
申请号：US15825875
申请日：2017-11-29
Applicant: FUJIFILM Corporation
Inventor： Takashi FUJIMOTO
CPC classification number: H01F1/11 , C01G49/06 , C01P2004/64 , C01P2006/42 , C08K3/22 , C08K2003/2268 , C08K2201/005 , C08K2201/01 , G11B5/70615 , G11B5/70642 , G11B5/714 , H01F1/0054 , H01F1/113
Abstract: Provided is an ε-iron oxide type ferromagnetic powder with a powder pH within a range of 4.8 to 6.8; and a method for manufacturing the ε-iron oxide type ferromagnetic powder and a composition containing at least the ε-iron oxide type ferromagnetic powder and a solvent.
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15.发明公开公开(公告)号：US20230290375A1
公开(公告)日：2023-09-14
申请号：US18182437
申请日：2023-03-13
Applicant: FUJIFILM Corporation
Inventor： Eiki OZAWA , Takashi FUJIMOTO
CPC classification number: G11B5/70642 , G11B5/714 , G11B5/7356 , G11B5/00813
Abstract: The magnetic recording medium includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. A magnetic tape cartridge and a magnetic recording and reproducing device include the magnetic recording medium. The ferromagnetic powder is an ε-iron oxide powder, and a ferromagnetic powder filling rate of a magnetic layer cross section obtained by observing a cross section of the magnetic layer with a scanning electron microscope is 0.60 or more and 0.80 or less.
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Patent Agency Ranking
16.发明公开公开(公告)号：US20230238025A1
公开(公告)日：2023-07-27
申请号：US18191983
申请日：2023-03-29
Applicant: FUJIFILM Corporation
Inventor： Eiki OZAWA , Takashi FUJIMOTO
CPC classification number: G11B5/70642 , G11B5/702 , G11B5/712
Abstract: Provided are: a magnetic recording medium including a non-magnetic support and a magnetic layer containing a ferromagnetic powder, in which the ferromagnetic powder is an ε-iron oxide powder, a vertical switching field distribution SFD of the magnetic recording medium is 0.20 or more and 3.00 or less at a measurement temperature of 25° C., and an inclination of SFD obtained from SFD at a measurement temperature of 10° C., SFD at a measurement temperature of 25° C., and SFD at a measurement temperature of 40° C. is 0.003° C.-1 or more and 0.080° C.-1 or less; a magnetic tape cartridge including the magnetic recording medium which is a magnetic tape; and a magnetic recording and reproducing device including the magnetic recording medium.
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17.发明申请公开(公告)号：US20230100028A1
公开(公告)日：2023-03-30
申请号：US17955137
申请日：2022-09-28
Applicant: FUJIFILM Corporation
Inventor： Takashi FUJIMOTO , Eiki OZAWA
Abstract: A magnetic recording medium including a magnetic layer including a ferromagnetic powder. The ferromagnetic powder is an ε-iron oxide powder, and a ratio of Hr (45°) to Hr (0°)(Hr (45°)/Hr (0°)) is 0.50 or less. The Hr (0°) is a residual coercive force Hr obtained by applying a pulse magnetic field having a pulse width of 0.76 ms in an in-plane direction of the magnetic recording medium, and the Hr (45°) is a residual coercive force Hr obtained by setting an angle of the magnetic recording medium in the in-plane direction to 0°, setting an angle of the magnetic recording medium in a vertical direction to 90°, and making a pulse magnetic field having a pulse width of 0.76 ms be incident from a direction inclined by 45° toward the vertical direction from the in-plane direction and applying the pulse magnetic field to the magnetic recording medium.
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18.发明申请公开(公告)号：US20210287707A1
公开(公告)日：2021-09-16
申请号：US17196296
申请日：2021-03-09
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA , Eiki OZAWA , Takashi FUJIMOTO
Abstract: The magnetic recording medium includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder in which the ferromagnetic powder is c-iron oxide powder, and a coercivity of a magnetic recording medium in a vertical direction measured after pressing the magnetic layer at a pressure of 70 atm is 3,000 Oe to 10,000 Oe.
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公开(公告)号：US20180358046A1
公开(公告)日：2018-12-13
申请号：US15996622
申请日：2018-06-04
Applicant: FUJIFILM Corporation
Inventor： Masashi SHIRATA , Takashi FUJIMOTO
CPC classification number: G11B5/78 , G11B5/70621
Abstract: Provided is a magnetic recording medium including: a non-magnetic support; and a magnetic layer including particles of at least one kind of epsilon type iron oxide-based compound selected from the group consisting of ε-Fe2O3 and a compound represented by Formula (1), an abrasive, and a binding agent, at least on one surface of the non-magnetic support, in which an average equivalent circle diameter of the particles of the epsilon type iron oxide-based compound is 7 nm to 18 nm, an average equivalent circle diameter of the abrasive in a plan view of the magnetic layer is 20 nm to 1,000 nm, and a coefficient of variation of the equivalent circle diameter of the abrasive is 30% to 60%. In Formula (1), A represents at least one kind of metal element other than Fe and a satisfies a relationship of 0
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公开(公告)号：US20180186654A1
公开(公告)日：2018-07-05
申请号：US15857861
申请日：2017-12-29
Applicant: FUJIFILM Corporation
Inventor： Takao MIZOGUCHI , Takashi FUJIMOTO
CPC classification number: C01G49/009 , C01G49/06 , C01P2002/52 , C01P2006/42 , G11B5/70642 , H01F1/11
Abstract: The ε-iron oxide type ferromagnetic powder contains Fe, a metal element selected from the group consisting of monovalent metal elements and divalent metal elements at a content rate within a range of 0.2 to 16.5 at % with respect to 100.0 at % of Fe, and a pentavalent metal element at a content rate within a range of 0.2 to 7.5 at % with respect to 100.0 at % of Fe, in which a total content rate of metal elements other than Fe is within a range of 2.5 to 24.0 at % with respect to 100.0 at % of Fe.
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