公开(公告)号：US20210249043A1

公开(公告)日：2021-08-12

申请号：US17242798

申请日：2021-04-28

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Eiki Ozawa ,  Atsushi Musha

IPC: G11B5/584 ,  G11B5/39 ,  G11B5/706 ,  G11B20/10 ,  G11B5/708 ,  G11B5/70 ,  G11B5/702 ,  G11B27/022 ,  G11B5/78 ,  G11B5/00 ,  B82Y10/00 ,  B82Y25/00

Abstract: The magnetic tape includes a non-magnetic support and a magnetic layer including ferromagnetic powder and a binding agent, in which the magnetic layer has a timing-based servo pattern, an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference (L99.9−L0.1) between a value L99.9 of a cumulative distribution function of 99.9% and a value L0.1 of a cumulative distribution function of 0.1% in a position deviation width from an ideal shape of the magnetic tape in a longitudinal direction is 180 nm or less, and an isoelectric point of a surface zeta potential of the magnetic layer is 3.8 or less.

公开(公告)号：US11069377B2

公开(公告)日：2021-07-20

申请号：US16832284

申请日：2020-03-27

Applicant: FUJIFILM Corporation

Inventor： Takahiro Iwamoto ,  Hidemasa Hosoda ,  Norihito Kasada ,  Takuto Kurokawa

IPC: G11B5/706 ,  G11B5/735 ,  G11B5/008 ,  G11B5/708 ,  G11B5/712 ,  G11B5/714

Abstract: Provided are a magnetic tape comprising a magnetic layer containing a ferromagnetic powder and a binding agent on a non-magnetic support, in which the magnetic layer contains an oxide abrasive, an average particle diameter of the oxide abrasive obtained from a secondary ion image acquired by irradiating a surface of the magnetic layer with a focused ion beam is 0.04 μm to 0.08 μm, and an absolute value ΔN of a difference between a refractive index Nxy measured with respect to an in-plane direction of the magnetic layer and a refractive index Nz measured with respect to a thickness direction of the magnetic layer is 0.25 to 0.40, and a magnetic recording and reproducing device including the magnetic tape.

公开(公告)号：US10891982B2

公开(公告)日：2021-01-12

申请号：US16848331

申请日：2020-04-14

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/78 ,  G11B5/706 ,  G11B5/702 ,  G11B5/735 ,  G11B5/70

Abstract: The magnetic tape includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which a magnetic tape total thickness is equal to or smaller than 5.30 μm, the magnetic layer has a servo pattern, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, and an isoelectric point of a surface zeta potential of the magnetic layer is equal to or greater than 5.5.

公开(公告)号：US10854231B2

公开(公告)日：2020-12-01

申请号：US16142560

申请日：2018-09-26

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Eiki Ozawa

IPC: G11B5/706 ,  G11B5/708 ,  G11B5/78 ,  G11B5/714 ,  G11B5/71 ,  G11B5/84 ,  G11B5/712

Abstract: Provided are a magnetic recording medium, in which a magnetic layer includes ferromagnetic hexagonal ferrite powder, a binding agent, and an oxide abrasive, an intensity ratio Int(110)/Int(114) 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 squareness ratio of the magnetic recording medium is 0.65 to 1.00, a coefficient of friction measured regarding a base portion of a surface of the magnetic layer is equal to or smaller than 0.30, and an average particle diameter of the oxide abrasive obtained from a secondary ion image obtained by irradiating the surface of the magnetic layer with a focused ion beam is 0.04 μm to 0.08 μm, and a magnetic recording and reproducing device including this magnetic recording medium.

公开(公告)号：US10854229B2

公开(公告)日：2020-12-01

申请号：US16038847

申请日：2018-07-18

Applicant: FUJIFILM Corporation

Inventor： Eiki Ozawa ,  Toshio Tada ,  Norihito Kasada ,  Takuto Kurokawa

IPC: G11B5/706 ,  G11B5/78 ,  G11B5/71 ,  G11B5/712 ,  G11B5/84 ,  G11B5/708 ,  G11B5/714

Abstract: Provided is a magnetic tape in which an Ra measured regarding a surface of a magnetic layer is equal to or smaller than 1.8 nm, Int(110)/Int(114) of a hexagonal ferrite crystal structure obtained by an XRD analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical squareness ratio of the magnetic tape is 0.65 to 1.00, full widths at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and equal to or smaller than 10.0 nm, and a difference between the spacings measured by optical interferometry regarding the surface of the back coating layer before and after performing the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm.

公开(公告)号：US10854228B2

公开(公告)日：2020-12-01

申请号：US16038771

申请日：2018-07-18

Applicant: FUJIFILM Corporation

Inventor： Takuto Kurokawa ,  Norihito Kasada ,  Toshio Tada ,  Eiki Ozawa

IPC: G11B5/706 ,  G11B5/708 ,  G11B5/71 ,  G11B5/714 ,  G11B5/84 ,  G11B5/78 ,  G11B5/735 ,  G11B5/712

Abstract: The magnetic tape includes a magnetic layer including ferromagnetic powder, non-magnetic powder, and a binding agent and a back coating layer including non-magnetic powder and a binding agent, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, a center line average surface roughness measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, 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 squareness ratio of the magnetic tape is 0.65 to 1.00, and a contact angle with respect to 1-bromonaphthalene measured regarding a surface of the back coating layer is 15.0° to 30.0°.

公开(公告)号：US20200302963A1

公开(公告)日：2020-09-24

申请号：US16825360

申请日：2020-03-20

Applicant: FUJIFILM Corporation

Inventor： Yuto Murata ,  Norihito Kasada ,  Yusuke Kagawa

IPC: G11B5/735 ,  G11B5/712

Abstract: Provided is a magnetic tape cartridge of a single reel type in which a magnetic tape is wound around a reel, in which the magnetic tape includes a non-magnetic support and a magnetic layer containing a ferromagnetic powder, and has a tape thickness of 5.3 μm or less, the magnetic layer includes a plurality of servo bands, and a difference (Ginner−Gouter) between a servo band interval Ginner in a range of 49 m to 51 m from a tape inner end and a servo band interval Gouter in a range of 49 m to 51 m from a tape outer end is −3.9 μm to 1.1 μm as a value measured on 100th day from a date of magnetic tape cartridge manufacture.

公开(公告)号：US10755735B2

公开(公告)日：2020-08-25

申请号：US16456965

申请日：2019-06-28

Applicant: FUJIFILM Corporation

Inventor： Eiki Ozawa ,  Norihito Kasada ,  Atsushi Musha

IPC: G11B5/584 ,  G11B5/596 ,  G11B5/71 ,  G11B15/46 ,  G11B5/012 ,  G11B5/09 ,  G11B5/70 ,  G11B5/588 ,  G11B5/54

Abstract: A magnetic tape apparatus, in which a tilt cos θ of the hexagonal ferrite powder with respect to a surface of the magnetic layer acquired by cross section observation by STEM is 0.85 to 1.00, a reading element unit includes a plurality of reading elements each of which reads data by a linear scanning method from a specific track region including a reading target track in a track region included in the magnetic tape, an extraction unit performs a waveform equalization process according to a deviation amount between positions of the magnetic tape and the reading element unit, with respect to each reading result for each reading element, to extract data derived from the reading target track from the reading result, and the deviation amount is determined in accordance with a result obtained by reading of the servo pattern included in the magnetic layer by a servo element.

公开(公告)号：US20200243110A1

公开(公告)日：2020-07-30

申请号：US16848331

申请日：2020-04-14

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/706 ,  G11B5/70 ,  G11B5/78 ,  G11B5/735 ,  G11B5/702

Abstract: The magnetic tape includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which a magnetic tape total thickness is equal to or smaller than 5.30 μm, the magnetic layer has a servo pattern, a center line average surface roughness Ra measured regarding a surface of the magnetic layer is equal to or smaller than 1.8 nm, and an isoelectric point of a surface zeta potential of the magnetic layer is equal to or greater than 5.5.

公开(公告)号：US10679655B2

公开(公告)日：2020-06-09

申请号：US16456745

申请日：2019-06-28

Applicant: FUJIFILM Corporation

Inventor： Eiki Ozawa ,  Norihito Kasada ,  Atsushi Musha

IPC: G11B5/09 ,  G11B5/584 ,  G11B5/008

Abstract: A magnetic tape apparatus, in which a magnetic tape includes a servo pattern in a magnetic layer, ΔSFD in a longitudinal direction of the magnetic tape is equal to or smaller than 0.50, a reading element unit includes a plurality of reading elements each of which reads data by a linear scanning method from a specific track region including a reading target track in a track region included in the magnetic tape, an extraction unit performs a waveform equalization process according to a deviation amount between positions of the magnetic tape and the reading element unit, with respect to each reading result for each reading element, to extract data derived from the reading target track from the reading result, and the deviation amount is determined in accordance with a result obtained by reading of the servo pattern included in the magnetic layer of the magnetic tape by a servo element.