公开(公告)号：US11302356B2

公开(公告)日：2022-04-12

申请号：US17155540

申请日：2021-01-22

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/706 ,  G11B5/78 ,  G11B5/008 ,  G11B5/735 ,  G11B5/714 ,  G11B5/708

Abstract: In the magnetic recording medium, a number distribution A of a plurality of bright regions, based on equivalent circle diameters thereof, in a binarized image of a secondary electron image obtained by imaging a surface of the magnetic layer by a scanning electron microscope at an acceleration voltage of 5 kV and a number distribution B of a plurality of dark regions, based on equivalent circle diameters thereof, in a binarized image of a secondary electron image obtained by imaging a surface of the magnetic layer by a scanning electron microscope at an acceleration voltage of 2 kV respectively satisfy a predetermined number distribution.

公开(公告)号：US11295776B2

公开(公告)日：2022-04-05

申请号：US17160977

申请日：2021-01-28

Applicant: FUJIFILM Corporation

Inventor： Yuto Murata ,  Yusuke Kaneko ,  Norihito Kasada

IPC: G11B5/735 ,  G11B5/706 ,  G11B20/12 ,  G11B5/712 ,  G11B5/73 ,  G11B15/43

Abstract: The magnetic tape satisfies TDSage+TDSenv−TC≤0.30 μm. TDSage is a maximum absolute value of a difference between the servo band interval obtained before a predetermined storage and the servo band interval obtained after the storage, TDSenv is a value calculated by multiplying a difference between a maximum value and a minimum value of the servo band interval respectively obtained under five predetermined environments by ½, TC is a value calculated by multiplying TDStens by 0.5 N, and TDStens is a ratio of a change in the servo band interval to a change in tension calculated from the servo band interval respectively obtained under five predetermined environments by applying a plurality of different tensions in the longitudinal direction of the magnetic tape.

公开(公告)号：US11270728B2

公开(公告)日：2022-03-08

申请号：US17022446

申请日：2020-09-16

Applicant: FUJIFILM Corporation

Inventor： Takuto Kurokawa ,  Naoki Sano ,  Norihito Kasada ,  Eiki Ozawa ,  Megumi Nakano

IPC: G11B5/735 ,  G11B5/733 ,  G11B5/73 ,  G11B5/78

Abstract: The magnetic recording medium includes a non-magnetic support; a magnetic layer that includes ferromagnetic powder on one surface side of the non-magnetic support; and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which a difference between a spacing measured on a surface of the back coating layer by optical interferometry under a pressure of 0.5 atm after n-hexane cleaning and a spacing measured on the surface of the back coating layer by optical interferometry under a pressure of 13.5 atm after n-hexane cleaning is 3 nm or less.

公开(公告)号：US11257518B2

公开(公告)日：2022-02-22

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 ,  G11B5/78 ,  G11B23/107 ,  G11B5/70 ,  G11B5/73

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：US11189318B2

公开(公告)日：2021-11-30

申请号：US16856853

申请日：2020-04-23

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/733 ,  G11B23/02 ,  G01B9/02 ,  B08B3/12 ,  G01B11/30 ,  G11B5/008

Abstract: The magnetic recording medium includes a non-magnetic support, a magnetic layer including a ferromagnetic powder on one surface of the non-magnetic support, and a back coating layer including a non-magnetic powder on the other surface of the non-magnetic support, in which a difference (Safter−Sbefore) between a spacing Safter measured by optical interferometry regarding a surface of the back coating layer after methyl ethyl ketone cleaning and a spacing Sbefore measured by optical interferometry regarding the surface of the back coating layer before methyl ethyl ketone cleaning is greater than 0 nm and equal to or smaller than 30.0 nm, and the non-magnetic support is an aromatic polyamide support having a moisture absorption of 2.2% or less.

公开(公告)号：US11127428B2

公开(公告)日：2021-09-21

申请号：US16777368

申请日：2020-01-30

Applicant: FUJIFILM Corporation

Inventor： Eiki Ozawa ,  Norihito Kasada ,  Atsushi Musha

IPC: G11B5/70 ,  G11B5/008

Abstract: The magnetic tape includes a non-magnetic support and a magnetic layer, in which an edge shape of the timing-based servo pattern, specified by magnetic force microscopy is a shape in which a difference 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 in which a difference between a spacing Safter measured on a surface of the magnetic layer by an optical interferometry after ethanol cleaning and a spacing Sbefore measured on the surface of the magnetic layer by an optical interferometry before ethanol cleaning is greater than 0 nm and 6.0 nm or less.

公开(公告)号：US20210287703A1

公开(公告)日：2021-09-16

申请号：US17195954

申请日：2021-03-09

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA ,  Norihito Kasada ,  Takashi Fujimoto

IPC: G11B5/706 ,  G11B5/78

Abstract: The magnetic recording medium includes: a non-magnetic support; and a magnetic layer containing a ferromagnetic powder, in which the ferromagnetic powder is an ε-iron oxide powder, and a transition temperature Tc of the magnetic recording medium measured after pressing the magnetic layer at a pressure of 70 atm is 80° C. to 240° C.

公开(公告)号：US11056141B2

公开(公告)日：2021-07-06

申请号：US16777312

申请日：2020-01-30

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Eiki Ozawa ,  Atsushi Musha

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

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：US10896692B2

公开(公告)日：2021-01-19

申请号：US15443094

申请日：2017-02-27

Applicant: FUJIFILM Corporation

Inventor： Takuto Kurokawa ,  Norihito Kasada ,  Masahito Oyanagi

IPC: G11B5/73 ,  G11B5/735 ,  G11B5/733 ,  G11B5/78

Abstract: The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on one surface of a nonmagnetic support and has a backcoat layer containing nonmagnetic powder and binder on the other surface thereof, wherein the thickness of the backcoat layer is less than or equal to 0.20 μm, and the contact angle for 1-bromonaphthalene that is measured on the surface of the backcoat layer falls within a range of 10.0° to 30.0°.

公开(公告)号：US10854234B2

公开(公告)日：2020-12-01

申请号：US16144428

申请日：2018-09-27

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Eiki Ozawa

IPC: G11B5/735 ,  G11B5/78 ,  G11B5/71 ,  G11B5/84 ,  G11B5/714 ,  G11B5/712 ,  G11B5/706 ,  G11B5/39 ,  G11B5/708

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 logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding a surface of the magnetic layer is equal to or smaller than 0.050, 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.