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公开(公告)号：US20190295587A1
公开(公告)日：2019-09-26
申请号：US16361597
申请日：2019-03-22
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA
Abstract: The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which an absolute value ΔN of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050.
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公开(公告)号：US20190130936A1
公开(公告)日：2019-05-02
申请号：US16232165
申请日：2018-12-26
Applicant: FUJIFILM Corporation
Inventor： Tetsuya KANEKO , Norihito KASADA , Eiki OZAWA
CPC classification number: G11B5/3909 , G11B5/00826 , G11B5/5526 , G11B5/584 , G11B5/5926 , G11B5/59633 , G11B5/59688 , G11B5/66 , G11B5/70
Abstract: The magnetic tape device includes: a magnetic tape; and a servo head, in which a magnetic tape transportation speed of the magnetic tape device is equal to or lower than 18 m/sec, the servo head is a magnetic head including a tunnel magnetoresistance effect type element as a servo pattern reading element, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer includes a servo pattern, and a coefficient of friction measured regarding a base portion of a surface of the magnetic layer is equal to or smaller than 0.30.
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公开(公告)号：US20180374504A1
公开(公告)日：2018-12-27
申请号：US16009461
申请日：2018-06-15
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA
Abstract: The magnetic recording medium includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which an isoelectric point of a surface zeta potential of the magnetic layer is equal to or greater than 5.5.
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公开(公告)号：US20180286452A1
公开(公告)日：2018-10-04
申请号：US15920635
申请日：2018-03-14
Applicant: FUJIFILM Corporation
Inventor： Eiki OZAWA , Norihito KASADA
CPC classification number: G11B5/714 , G11B5/00813 , G11B5/3909 , G11B5/584 , G11B5/70 , G11B5/70615
Abstract: The magnetic tape device includes a TMR head and a magnetic tape, in which the magnetic tape includes fatty acid ester in a magnetic layer, Ra measured regarding a surface of the magnetic layer is 2.0 nm or smaller, full widths at half maximum of spacing distribution measured by optical interferometry regarding a surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and 7.0 nm or smaller, a difference between spacings before and after the vacuum heating is greater than 0 nm and 8.0 nm or smaller, and a ratio of an average area Sdc of a magnetic cluster of the magnetic tape in a DC demagnetization state and an average area Sac of a magnetic cluster thereof in an AC demagnetization state measured with a magnetic force microscope is 0.80 to 1.30.
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公开(公告)号：US20180286450A1
公开(公告)日：2018-10-04
申请号：US15920544
申请日：2018-03-14
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA , Eiki OZAWA
CPC classification number: G11B5/714 , G11B5/00813 , G11B5/3909 , G11B5/70 , G11B5/70615 , G11B5/70678 , G11B5/82
Abstract: The magnetic tape device includes a magnetic tape including a magnetic layer; and a TMR head (reproducing head), in which an intensity ratio of a peak intensity of a diffraction peak of a (110) plane with respect to a peak intensity of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on the surface of the magnetic layer at a photoelectron take-off angle of 10 degrees is 45 to 65 atom %.
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Patent Agency Ranking
公开(公告)号：US20180240495A1
公开(公告)日：2018-08-23
申请号：US15900345
申请日：2018-02-20
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA
CPC classification number: G11B5/712 , G11B5/00813 , G11B5/70 , G11B5/70615 , G11B5/70678 , G11B5/7085 , G11B5/78
Abstract: The magnetic tape includes a non-magnetic support; a non-magnetic layer including non-magnetic powder and a binding agent on the non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic layer, in which the total thickness of the non-magnetic layer and the magnetic layer is equal to or smaller than 0.60 μm, the magnetic layer includes an abrasive, a percentage of a plan view maximum area of the abrasive confirmed in a region having a size of 4.3 μm×6.3 μm of the surface of the magnetic layer with respect to the total area of the region, obtained by plane observation performed by using a scanning electron microscope is equal to or greater than 0.02% and less than 0.06%, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.
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公开(公告)号：US20180240481A1
公开(公告)日：2018-08-23
申请号：US15899430
申请日：2018-02-20
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA , Eiki OZAWA
CPC classification number: G11B5/584 , G11B5/00813 , G11B5/3909 , G11B5/70 , G11B5/70678 , G11B5/78
Abstract: The magnetic tape device includes a TMR head as a servo head; and a magnetic tape which includes a magnetic layer including ferromagnetic hexagonal ferrite powder and a binding agent, and including a servo pattern, an XRD intensity ratio (Int(110)/Int(114)) of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.
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公开(公告)号：US20180240479A1
公开(公告)日：2018-08-23
申请号：US15900144
申请日：2018-02-20
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA , Eiki OZAWA
CPC classification number: G11B5/3909 , G11B5/00813 , G11B5/00817 , G11B5/21 , G11B5/70 , G11B5/78
Abstract: The magnetic tape device includes a magnetic tape; and a TMR head as a reproducing head, in which a center line average surface roughness Ra measured regarding a surface of the magnetic layer of the magnetic tape is equal to or smaller than 2.0 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1: ΔSFD=SFD25° C.−SFD−190° C. is equal to or smaller than 0.50, wherein, in Expression 1, the SFD25° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is a switching field distribution SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.
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公开(公告)号：US20180240478A1
公开(公告)日：2018-08-23
申请号：US15899587
申请日：2018-02-20
Applicant: FUJIFILM Corporation
Inventor： Norihito KASADA , Eiki OZAWA
Abstract: The magnetic tape device includes a TMR head as a reproducing head; and a magnetic tape which includes a non-magnetic support, and a magnetic layer including ferromagnetic hexagonal ferrite powder and a binding agent on the non-magnetic support, an XRD intensity ratio (Int(110)/Int(114)) of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, and a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050.
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公开(公告)号：US20180082710A1
公开(公告)日：2018-03-22
申请号：US15705531
申请日：2017-09-15
Applicant: FUJIFILM Corporation
Inventor： Toshio TADA , Norihito KASADA , Masahito OYANAGI , Akinori SUGISHIMA , Kengo SAITO
Abstract: The magnetic recording medium has a non-magnetic support and a magnetic layer which is provided on the support and contains ferromagnetic powder and a binder, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer contains an abrasive, an intensity ratio (Int (110)/Int (114)) of a peak intensity Int (110) of a diffraction peak of (110) plane of a crystal structure of the hexagonal ferrite, determined by performing X-ray diffraction analysis on the magnetic layer by using an In-Plane method, to a peak intensity Int (114) of a diffraction peak of (114) plane of the crystal structure is equal to or higher than 0.5 and equal to or lower than 4.0, and a squareness ratio in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00. The present invention also provides a method for manufacturing the magnetic recording medium.
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