公开(公告)号：US20240331727A1

公开(公告)日：2024-10-03

申请号：US18574137

申请日：2022-03-31

Applicant: Sony Group Corporation

Inventor： Noboru SEKIGUCHI ,  Minoru YAMAGA ,  Futoshi SASAKI

IPC: G11B5/733 ,  G11B5/706 ,  G11B5/708 ,  G11B5/714

CPC classification number: G11B5/733 ,  G11B5/70678 ,  G11B5/7085 ,  G11B5/714

Abstract: Provided is a magnetic recording medium capable of ensuring good electromagnetic conversion characteristics while suppressing an increase in a standard deviation σPES due to traveling many times.
The magnetic recording medium sequentially includes a base, an underlayer, and a magnetic layer. The magnetic layer includes magnetic particles, conductive first particles, and second particles having a Mohs hardness of 7.0 or more. The magnetic layer has a concavoconvex shape on a magnetic surface, and the concavoconvex shape includes a first protrusion including the first particles and a second protrusion including the second particles. A ratio H1/H2 of an average height H1 of the first protrusion and an average height H2 of the second protrusion satisfies H1/H2≤2.3, a height range ΔH obtained from statistical information on a height of the concavoconvex shape satisfies 3.00 nm≤ΔH≤6.00 nm, and a gradient range ΔA obtained from statistical information on a gradient of the concavoconvex shape satisfies 4.00 degrees≤ΔA≤9.00 degrees.

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：US20230306995A1

公开(公告)日：2023-09-28

申请号：US18187017

申请日：2023-03-21

Applicant: FUJIFILM Corporation

Inventor： Toshio TADA ,  Hiroyuki Suzuki ,  Megumi Nakano

IPC: G11B5/708 ,  G11B5/72 ,  G11B5/78

CPC classification number: G11B5/708 ,  G11B5/72 ,  G11B5/78

Abstract: The magnetic recording medium is used in a magnetic recording and reproducing device in which a reproduction bit size S is 40,000 nm2 or less, and a numerical value of a residual magnetic flux density Brvertical, which is expressed in a unit G, in a vertical direction of the magnetic recording medium is X or more. The X is a value calculated as X = -0.01S + 1550.

公开(公告)号：US11423932B2

公开(公告)日：2022-08-23

申请号：US17399241

申请日：2021-08-11

Applicant: FUJIFILM Corporation

Inventor： Eiki Ozawa ,  Norihito Kasada ,  Atsushi Musha

IPC: G11B5/584 ,  G11B5/706 ,  G11B5/702 ,  G11B5/70 ,  G11B5/708 ,  G11B20/10 ,  G11B23/50 ,  G11B5/78 ,  G11B27/022 ,  G01B11/06 ,  G11B5/00 ,  B82Y25/00 ,  B82Y10/00

Abstract: The magnetic tape includes a non-magnetic support; and a magnetic layer 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 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 a difference between a spacing Safter measured on a surface of the magnetic layer by an optical interferometry after methyl-ethyl-ketone cleaning and a spacing Sbefore measured on the surface of the magnetic layer by an optical interferometry before methyl-ethyl-ketone cleaning is greater than 0 nm and 15.0 nm or less.

公开(公告)号：US11373680B2

公开(公告)日：2022-06-28

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：US11361793B2

公开(公告)日：2022-06-14

申请号：US16361597

申请日：2019-03-22

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

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

Abstract: The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which an absolute value ΔN of a difference between a refractive index Nxy measured regarding an in-plane direction of the magnetic layer and a refractive index Nz measured regarding a thickness direction of the magnetic layer is 0.25 to 0.40, and 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.

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：US11127429B2

公开(公告)日：2021-09-21

申请号：US16092949

申请日：2017-04-13

Applicant: DIC Corporation

Inventor： Akira Fukasawa ,  Toshiaki Adachi ,  Daisuke Yano

IPC: G11B5/72 ,  G11B5/84 ,  G06K19/06 ,  G11B5/708 ,  G11B5/80

Abstract: A problem to be solved by the present invention is to provide a magnetic recording medium having a jet-black magnetic stripe which is not tinged with red. The present invention is directed to a magnetic recording medium including: a magnetic recording layer on a substrate; and a protective layer (a) on the magnetic recording layer, wherein the protective layer (a) contains an aniline coloring material. The magnetic recording medium is advantageous in that the magnetic stripe is jet-black and has excellent design properties, and therefore can be widely used for credit cards, bank cards and the like.

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：US10910008B2

公开(公告)日：2021-02-02

申请号：US16115962

申请日：2018-08-29

Applicant: FUJIFILM Corporation

Inventor： Masahiko Mori ,  Yoshihiro Sawayashiki

IPC: G11B5/714 ,  G11B5/733 ,  G11B5/708

Abstract: The magnetic recording medium includes a non-magnetic support; a non-magnetic layer including a non-magnetic powder and a binding agent on the non-magnetic support; and a magnetic layer including a ferromagnetic powder, a binding agent, and a non-magnetic powder on the non-magnetic layer, in which a skewness Rsk obtained using an atomic force microscope in a measurement region of a surface of the magnetic layer having a size of 5 μm×5 μm is greater than 0, a maximum peak height Rmax is equal to or smaller than 30.0 nm, and the number of projections having a height equal to or greater than 10 nm is equal to or greater than 10, and a magnetic recording and reproducing device including: this magnetic recording medium; and a magnetic head.