公开(公告)号：US20240282336A1

公开(公告)日：2024-08-22

申请号：US18649412

申请日：2024-04-29

Applicant: FUJIFILM Corporaton

Inventor： Norihito KASADA ,  Yusuke Kaneko

IPC: 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 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 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：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：US20230317109A1

公开(公告)日：2023-10-05

申请号：US18015252

申请日：2021-07-14

Applicant: Sony Group Corporation

Inventor： Hiroshi KAWAI

IPC: G11B5/706 ,  G11B5/714 ,  G11B5/735 ,  G11B5/592 ,  G11B23/027

CPC classification number: G11B5/70678 ,  G11B5/714 ,  G11B5/7356 ,  G11B5/5928 ,  G11B23/027

Abstract: Provided is a magnetic recording medium capable of suppressing deterioration of running stability even after repeated recording or reproduction is performed.
The magnetic recording medium is a magnetic recording medium having a tape shape, and includes a substrate, an underlayer provided on one surface of the substrate and including a magnetic powder and a binder, and a magnetic layer provided on the underlayer and including a nonmagnetic powder and a binder. The magnetic recording medium has an average thickness of 5.3 μm or less. In a case where a correlation between an amount of projected particles and an erosion depth is obtained in each of the underlayer and the magnetic layer by a micro slurry-jet erosion (MSE), a calculation of a ratio of a particle amount required to wear an erosion depth range to the erosion depth range is performed in each of the underlayer and the magnetic layer on the basis of the correlation, and a result of the calculation is defined as an MSE resistance value of each of the underlayer and the magnetic layer, the ratio of the MSE resistance value of the magnetic layer to the MSE resistance value of the underlayer is in a range of 0.45 or more and 0.80 or less.

公开(公告)号：US20240355355A1

公开(公告)日：2024-10-24

申请号：US18680136

申请日：2024-05-31

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA

IPC: G11B5/592 ,  G11B5/706 ,  G11B5/714 ,  G11B5/735 ,  G11B5/78

CPC classification number: G11B5/5928 ,  G11B5/70678 ,  G11B5/714 ,  G11B5/7356 ,  G11B5/78

Abstract: Provided is a magnetic tape, in which, in an environment of a temperature of 32° C. and a relative humidity of 80%, a frictional force F45° on a magnetic layer surface with respect to an LTO8 head measured at a head tilt angle of 45° is 4 gf or more and 15 gf or less, and standard deviation of a frictional force F on the magnetic layer surface with respect to the LTO8 head respectively measured at head tilt angles of 0°, 15°, 30°, and 45° is 10 gf or less. The magnetic tape includes a polyethylene naphthalate support having a Young's modulus in a width direction of 10000 MPa or more.

公开(公告)号：US20240203454A1

公开(公告)日：2024-06-20

申请号：US18538367

申请日：2023-12-13

Applicant: FUJIFILM Corporation

Inventor： Yujin SHIBATA

IPC: G11B5/78 ,  G11B5/008 ,  G11B5/66 ,  G11B5/73 ,  G11B5/735

CPC classification number: G11B5/78 ,  G11B5/00817 ,  G11B5/66 ,  G11B5/7356 ,  G11B5/7369 ,  G11B2220/956

Abstract: The magnetic tape includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder. 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 2 kV, the number of dark regions having an equivalent circle diameter of 75 nm or more and less than 125 nm is 20 or more and 1500 or less, and standard deviation σ of the number of the dark regions in a width direction of the surface of the magnetic layer is 400 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：US20240105227A1

公开(公告)日：2024-03-28

申请号：US18524221

申请日：2023-11-30

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Yuto MURATA ,  Nagisa YAMASAKI

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

CPC classification number: G11B5/70 ,  G11B5/00813 ,  G11B5/00826 ,  G11B5/4893 ,  G11B5/00856 ,  G11B5/7356

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：US20230386515A1

公开(公告)日：2023-11-30

申请号：US18449307

申请日：2023-08-14

Applicant: FUJIFILM Corporation

Inventor： Takashi FUJIMOTO ,  Eiki Ozawa

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

CPC classification number: G11B5/70621 ,  G11B5/7356 ,  G11B5/7021 ,  G11B5/78

Abstract: Provided are a magnetic recording medium including a non-magnetic support, and a magnetic layer including a ferromagnetic powder. The ferromagnetic powder is an ε-iron oxide powder, and an intensity ratio (Int1/Int2) of diffraction intensities obtained by an X-ray diffraction analysis of the magnetic layer using an In-Plane method is 1.0 or more and 6.5 or less; and a magnetic tape cartridge and a magnetic recording and reproducing device each including the magnetic recording medium.

公开(公告)号：US20230154491A1

公开(公告)日：2023-05-18

申请号：US18052406

申请日：2022-11-03

Applicant: FUJIFILM Corporation

Inventor： Junya SAWADA ,  Noriko Oyanagi

IPC: G11B5/66 ,  G11B5/708 ,  G11B5/735

CPC classification number: G11B5/676 ,  G11B5/7085 ,  G11B5/7356 ,  G11B5/00813

Abstract: The magnetic recording medium includes a non-magnetic support; and a magnetic layer containing a ferromagnetic powder, in which the magnetic layer includes an abrasive, the abrasive is a carbide, an average primary particle diameter of the abrasive is 10 nm or more and 100 nm or less, and in an electron microscope image of a surface of the magnetic layer, assuming that a total area occupied by the abrasive is 100%, a ratio of an area occupied by the abrasive present in an aggregated state having a maximum Feret diameter of 0.2 µm or more is 50% or more.