公开(公告)号：US12217780B2

公开(公告)日：2025-02-04

申请号：US18524221

申请日：2023-11-30

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Yuto Murata ,  Nagisa Yamasaki

IPC: G11B5/78 ,  G11B5/008 ,  G11B5/48 ,  G11B5/70 ,  G11B5/735

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. In a binarized image of a secondary electron image obtained by imaging a surface of the magnetic layer with a scanning electron microscope at an acceleration voltage of 5 kV, the number of bright regions having an equivalent circle diameter of 60 nm or more and less than 120 nm is 8000 or more and 30000 or less. Standard deviation σ of the number of the bright regions in a width direction of the surface of the magnetic layer is 2000 or less.

公开(公告)号：US20250014602A1

公开(公告)日：2025-01-09

申请号：US18759188

申请日：2024-06-28

Applicant: FUJIFILM Corporation

Inventor： Nobuhito Onozuka ,  Norihito Kasada ,  Ryosuke Yumiyama ,  Junya Sawada

IPC: G11B5/73 ,  G11B5/588

Abstract: The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder. A magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape. CS VIVA 0.1, which is a height that is obtained by measuring a surface of the magnetic layer with an atomic force microscope and at which a cutout length is 0.1% with a length of one side of a measurement region as 100%, is 4 nm or more and 10 nm or less, and standard deviation a of the CS VIVA 0.1 in a width direction of the surface of the magnetic layer is 1.0 nm or less.

公开(公告)号：US20250014599A1

公开(公告)日：2025-01-09

申请号：US18758432

申请日：2024-06-28

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Nobuhito Onozuka ,  Junya Sawada ,  Ryosuke Yumiyama

IPC: G11B5/73 ,  G11B5/588

Abstract: The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder. A magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape. A core void volume Vvc specified in international organization for standardization (ISO) 25178 on a surface of the magnetic layer is 1.200 nm3 or more and 3.000 nm3 or less, and standard deviation a of the Vvc in a width direction of the surface of the magnetic layer is 0.120 nm3 or less.

公开(公告)号：US20250014598A1

公开(公告)日：2025-01-09

申请号：US18759114

申请日：2024-06-28

Applicant: FUJIFILM Corporation

Inventor： Ryosuke YUMIYAMA ,  Norihito Kasada ,  Nobuhito Onozuka ,  Junya Sawada

IPC: G11B5/706 ,  G11B5/55 ,  G11B5/714 ,  G11B5/735 ,  G11B5/78

Abstract: The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder. A magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape. A protruding peak height Spk specified in ISO 25178 on a surface of the magnetic layer is 1.5 nm or more and 3.0 nm or less, and standard deviation σ of the Spk in a width direction of the surface of the magnetic layer is 0.5 nm or less.

公开(公告)号：US12009017B2

公开(公告)日：2024-06-11

申请号：US17730763

申请日：2022-04-27

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Yusuke Kaneko

IPC: G11B5/48 ,  G11B5/592 ,  G11B5/706 ,  G11B5/735 ,  G11B5/78 ,  G11B23/107

CPC classification number: G11B5/5928 ,  G11B5/70678 ,  G11B5/7356 ,  G11B5/78 ,  G11B23/107

Abstract: In the magnetic tape, in a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage in an environment of a temperature of 32° C. and relative humidity of 55% and a servo band spacing obtained after storage in the environment for a storage time T is set to A, and T is defined as 24 hours, 48 hours, 72 hours, 96 hours, or 120 hours, a medium life calculated by a linear function of A and a logarithm logeT of T, that are derived from a value of A and a value of the logarithm logeT of T obtained for each T is 3 years or longer. The medium life is T in a case where the A satisfies Equation 1: A=1.5−B.

公开(公告)号：US11900977B2

公开(公告)日：2024-02-13

申请号：US17955113

申请日：2022-09-28

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/706 ,  G11B5/733 ,  G11B5/78

CPC classification number: G11B5/70615 ,  G11B5/7334 ,  G11B5/78

Abstract: A magnetic tape in which an arithmetic average roughness Ra measured at a surface of a magnetic layer with an atomic force microscope is 2.0 nm 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：US11862214B2

公开(公告)日：2024-01-02

申请号：US17953149

申请日：2022-09-26

Applicant: FUJIFILM Corporation

Inventor： Yujin Shibata ,  Norihito Kasada ,  Takuto Kurokawa ,  So Matsuyama

IPC: G11B5/78 ,  G11B5/65 ,  G11B23/107 ,  G11B5/584 ,  G11B5/733 ,  G11B5/008

CPC classification number: G11B5/653 ,  G11B5/00813 ,  G11B5/584 ,  G11B5/733 ,  G11B5/78 ,  G11B23/107

Abstract: The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder, in which an edge portion Ra which is an arithmetic average roughness Ra measured at an edge portion of a surface of the magnetic layer is 1.50 nm or less, a central portion Ra which is an arithmetic average roughness Ra measured at a central portion of the surface of the magnetic layer is 0.30 nm to 1.30 nm, and a Ra ratio (central portion Ra/edge portion Ra) is 0.75 to 0.95.

公开(公告)号：US11842752B2

公开(公告)日：2023-12-12

申请号：US17680961

申请日：2022-02-25

Applicant: FUJIFILM Corporation

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

IPC: G11B23/107 ,  G11B5/78

CPC classification number: G11B23/107 ,  G11B5/78

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, and the roundness of the trajectory of one rotation drawn by the magnetic tape in a case where the wound magnetic tape is pulled out from the core is 100 μm or less as the arithmetic mean of the measured values at three points in the width direction of the magnetic tape.

公开(公告)号：US20230206948A1

公开(公告)日：2023-06-29

申请号：US18170683

申请日：2023-02-17

Applicant: FUJIFILM Corporation

Inventor： Toru NAKAO ,  Norihito Kasada ,  Tetsuya KANEKO ,  Atsushi MUSHA

IPC: G11B5/584 ,  G11B23/027 ,  G11B15/43

CPC classification number: G11B5/584 ,  G11B23/027 ,  G11B15/43

Abstract: A magnetic tape cartridge includes a case in which a magnetic tape is accommodated and a storage medium provided in the case. At least one of reading or writing of data is performed by a plurality of magnetic elements, which are linearly disposed, with respect to the magnetic tape pulled out from the case. A disposition direction of the plurality of magnetic elements is tilted toward an entire length direction side of the magnetic tape with respect to a width direction of the magnetic tape. The storage medium stores tilt feature information indicating a feature of tilt of the disposition direction with respect to the width direction.

公开(公告)号：US11631429B2

公开(公告)日：2023-04-18

申请号：US17378783

申请日：2021-07-19

Applicant: FUJIFILM Corporation

Inventor： Yusuke Kaneko ,  Norihito Kasada

IPC: G11B23/08 ,  G11B5/73 ,  G11B5/78 ,  G11B5/733 ,  G11B23/107

Abstract: The magnetic tape cartridge includes a magnetic tape that is accommodated in the magnetic tape cartridge while being wound around a reel hub. A water absorption amount of the magnetic tape measured after the magnetic tape cartridge is stored in a storage environment of a temperature of 32° C. and a relative humidity of 80% for 10 days is more than 0.30 g as a value in terms of a length of the magnetic tape of 1000 m, and the water absorption amount is a value measured in a measurement environment with a temperature of 21° C. and a relative humidity of 50% within 1 hour after the storage.