公开(公告)号：US12300276B2

公开(公告)日：2025-05-13

申请号：US18421433

申请日：2024-01-24

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B3/04 ,  G11B5/702 ,  G11B5/706 ,  G11B33/04

Abstract: Provided is a magnetic tape, in which, in an environment of a temperature of 23° C. and a relative humidity of 50%, an AlFeSil abrasion value45° of a magnetic layer surface measured at a tilt angle of 45° of an AlFeSil square bar is 20 μm or more and 50 μm or less, standard deviation of an AlFeSil abrasion value of the magnetic layer surface measured at each of tilt angles of 0°, 15°, 30°, and 45° of the AlFeSil square bar is 30 μm or less. The tilt angle of the AlFeSil square bar is an angle formed by a longitudinal direction of the AlFeSil square bar and a width direction of the magnetic tape. A magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape.

公开(公告)号：US12106789B2

公开(公告)日：2024-10-01

申请号：US18298084

申请日：2023-04-10

Applicant: FUJIFILM Corporation

Inventor： Nagisa Yamasaki ,  Norihito Kasada ,  Yuto Murata

IPC: G11B5/78 ,  G11B5/70 ,  G11B5/592 ,  G11B5/84

CPC classification number: G11B5/78 ,  G11B5/70 ,  G11B5/5928 ,  G11B5/84

Abstract: The magnetic tape includes: a non-magnetic support; and a magnetic layer containing a ferromagnetic powder, and a magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape. The number of recesses existing on a surface of the magnetic layer and having an equivalent circle diameter of 0.15 μm or more and 0.25 μm or less is 100 or more and 2500 or less per an area of 40 μm×40 μm. Standard deviation σ of the number of the recesses in a width direction of the surface of the magnetic layer is 100 or less.

公开(公告)号：US12087337B2

公开(公告)日：2024-09-10

申请号：US17872651

申请日：2022-07-25

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/584 ,  G11B5/127 ,  G11B5/73 ,  G11B5/78

CPC classification number: G11B5/584 ,  G11B5/73927 ,  G11B5/78 ,  G11B5/127 ,  G11B5/739

Abstract: A magnetic tape device. The angle θ formed by the axis of the element array of the magnetic head with respect to a width direction of the magnetic tape is changed during running of the magnetic tape in the magnetic tape device. In a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage in a predetermined environment and a servo band spacing obtained after storage in the environment for a storage time T is defined as A, and T is set to a plurality of predetermined times, a medium life calculated by a linear function of A and a logarithm loge T of T, that are derived from a value of A and a value of the logarithm loge T of T obtained for each T is 5 years or longer.

公开(公告)号：US11922981B2

公开(公告)日：2024-03-05

申请号：US17872464

申请日：2022-07-25

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/48 ,  G11B5/008

CPC classification number: G11B5/4893 ,  G11B5/00821

Abstract: A magnetic tape device. The angle θ formed by the axis of the element array of the magnetic head with respect to a width direction of the magnetic tape is changed during running of the magnetic tape in the magnetic tape device. In a case where predetermined storage is defined as one cycle, a maximum value of an absolute value of a difference between a servo band spacing obtained before performing the storage and a servo band spacing obtained after the storage of N cycles is defined as A, and N is set to 1, 2, 3, 4, or 5, a medium life calculated by a linear function of A and a logarithm loge T of T, that are derived from a value of A and a value of the logarithm loge T of total storage time T of the storage of N cycles is 5 years or longer.

公开(公告)号：US11894033B2

公开(公告)日：2024-02-06

申请号：US17954800

申请日：2022-09-28

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/733 ,  G11B5/78

CPC classification number: G11B5/7334 ,  G11B5/78

Abstract: A magnetic tape in which a vertical switching field distribution SFD of the magnetic tape is 1.5 or less, and in an environment with a temperature of 32° C. and a relative humidity of 80%, a frictional force F45° on the surface of the magnetic layer with respect to an LTO8 head measured at a head tilt angle of 45° is 4 gf to 15 gf, and a standard deviation of a frictional force F on the surface of the magnetic layer with respect to the LTO8 head measured at each of head tilt angles of 0°, 15°, 30°, and 45° is 10 gf or less.

公开(公告)号：US11869558B2

公开(公告)日：2024-01-09

申请号：US17955035

申请日：2022-09-28

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/735 ,  G11B5/78 ,  G11B5/708

CPC classification number: G11B5/7356 ,  G11B5/7085 ,  G11B5/78

Abstract: A magnetic tape in which a tape thickness of the magnetic tape is 5.2 μm or less, and in an environment with a temperature of 23° C. and a relative humidity of 50%, an AlFeSil abrasion value45° of a surface of the magnetic layer measured at a tilt angle of 45° of an AlFeSil prism is 20 μm to 50 μm, a standard deviation of an AlFeSil abrasion value of the surface of the magnetic layer measured at each of tilt angles of 0°, 15°, 30°, and 45° of the AlFeSil prism is 30 μm or less, and the tilt angle of the AlFeSil prism is an angle formed by a longitudinal direction of the AlFeSil prism and a width direction of the magnetic tape.

公开(公告)号：US11869552B2

公开(公告)日：2024-01-09

申请号：US17953953

申请日：2022-09-27

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/55 ,  G11B5/735 ,  G11B5/65 ,  G11B5/78

CPC classification number: G11B5/5504 ,  G11B5/658 ,  G11B5/7356 ,  G11B5/7358 ,  G11B5/78

Abstract: A magnetic tape in which a tape thickness of the magnetic tape is 5.2 μm or less, and in an environment with a temperature of 32° C. and a relative humidity of 80%, a frictional force F45° on the surface of the magnetic layer with respect to an LTO8 head measured at a head tilt angle of 45° is 4 gf to 15 gf, and a standard deviation of a frictional force F on the surface of the magnetic layer with respect to the LTO8 head measured at each of head tilt angles of 0°, 15°, 30°, and 45° is 10 gf or less.

公开(公告)号：US11869551B2

公开(公告)日：2024-01-09

申请号：US17872464

申请日：2022-07-25

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/48 ,  G11B5/008

CPC classification number: G11B5/4893 ,  G11B5/00821

Abstract: A magnetic tape device. The angle θ formed by the axis of the element array of the magnetic head with respect to a width direction of the magnetic tape is changed during running of the magnetic tape in the magnetic tape device. In a case where predetermined storage is defined as one cycle, a maximum value of an absolute value of a difference between a servo band spacing obtained before performing the storage and a servo band spacing obtained after the storage of N cycles is defined as A, and N is set to 1, 2, 3, 4, or 5, a medium life calculated by a linear function of A and a logarithm loge T of T, that are derived from a value of A and a value of the logarithm loge T of total storage time T of the storage of N cycles is 5 years or longer.

公开(公告)号：US11823711B2

公开(公告)日：2023-11-21

申请号：US17847970

申请日：2022-06-23

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Yusuke Kaneko

IPC: G11B20/12 ,  G11B5/008

CPC classification number: G11B20/1201 ,  G11B5/00813

Abstract: Regarding 100 reels of magnetic tape cartridges in the magnetic tape cartridge group, in a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage in a predetermined environment and a servo band spacing obtained after storage in the predetermined environment for storage time T is defined as A, an arithmetic mean of a medium lives calculated by a linear function derived from a value of A and a value of the logarithm loge T of T is 4 years or longer and 3σ is 1 year or shorter. The medium life is T in a case where A satisfies Equation 1=1.5−B, and the B is a value calculated by multiplying a difference between a maximum value and a minimum value of the servo band spacings obtained in each of the five predetermined environments by ½.

公开(公告)号：US11735219B2

公开(公告)日：2023-08-22

申请号：US17680904

申请日：2022-02-25

Applicant: FUJIFILM Corporation

Inventor： Shota Kamimura ,  Yuto Murata ,  Tomohide Ueyama ,  Norihito Kasada

IPC: G11B5/78 ,  G11B5/00 ,  G11B15/093 ,  G11B15/43

CPC classification number: G11B5/78 ,  G11B15/43 ,  B65H2701/378

Abstract: The magnetic tape container includes a core around which a magnetic tape is wound. The magnetic tape includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. A maximum value of a deviation of a center position of an average minimum region reference circle of a trajectory of one rotation drawn by the magnetic tape, in a case where the wound magnetic tape is drawn out from the core core is 100 μm or less for three points of the magnetic tape in a width direction.