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：US20250006225A1

公开(公告)日：2025-01-02

申请号：US18759153

申请日：2024-06-28

Applicant: FUJIFILM Corporation

Inventor： Junya SAWADA ,  Norihito KASADA ,  Nobuhito ONOZUKA ,  Ryosuke YUMIYAMA

IPC: G11B5/706 ,  G11B5/592 ,  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 dale void volume Vvv specified in ISO 25178 on a surface of the magnetic layer is 0.100 nm3 or more and 0.350 nm3 or less, and standard deviation a of the Vvv in a width direction of the surface of the magnetic layer is 0.020 nm3 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：US12051454B2

公开(公告)日：2024-07-30

申请号：US18054809

申请日：2022-11-11

Applicant: FUJIFILM Corporation

Inventor： Atsushi Morooka

IPC: G11B5/71 ,  G11B5/66 ,  G11B5/706 ,  G11B5/714

CPC classification number: G11B5/674 ,  G11B5/70626 ,  G11B5/714

Abstract: The magnetic recording medium has an arithmetic average roughness Ra of a surface of a magnetic layer is 2.2 nm or less, a fluorine concentration A obtained by X-ray photoelectron spectroscopy performed on a surface of the magnetic layer at a photoelectron take-off angle of 10 degrees being 5 atom % or more and 50 atom % or less, and B, which is calculated by Equation 1 from an integrated intensity Ftotal of fragments derived from a fluorine-containing compound obtained for an entire region in a thickness direction of a cross section of the magnetic layer by line profile analysis of TOF-SIMS and an integrated intensity Fupper of fragments derived from a fluorine compound obtained for a region from the surface of the magnetic layer to an intermediate thickness in the thickness direction of the cross section, being 60% or more and 95% or less, Equation 1:B=(Fupper/Ftotal)×100.

公开(公告)号：US11670334B2

公开(公告)日：2023-06-06

申请号：US17394567

申请日：2021-08-05

Applicant: FUJIFILM Corporation

Inventor： Wataru Kikuchi ,  Masatoshi Yumoto ,  Takashi Imai

IPC: G11B5/706 ,  G11B5/702 ,  G11B5/714 ,  G11B5/70

CPC classification number: G11B5/70678 ,  G11B5/7013 ,  G11B5/7023 ,  G11B5/7028 ,  G11B5/714

Abstract: The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including a ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer further includes a compound including a polyalkyleneimine chain and a vinyl polymer chain. The composition for a magnetic recording medium includes: ferromagnetic powder; and a compound including a polyalkyleneimine chain and a vinyl polymer chain.

公开(公告)号：US11615812B2

公开(公告)日：2023-03-28

申请号：US16649482

申请日：2019-10-03

Applicant: Sony Corporation

Inventor： Minoru Yamaga ,  Takanobu Iwama ,  Jun Takahashi

IPC: G11B5/71 ,  G11B5/706 ,  G11B5/735 ,  G11B5/73 ,  G11B5/65 ,  G11B5/66 ,  C10M129/40 ,  C10M129/70 ,  G11B5/714 ,  G11B5/78

Abstract: An object is to provide a magnetic recording medium having excellent traveling stability and a thin total thickness.
The present technology provides a tape-shaped magnetic recording medium including: a magnetic layer; an underlayer; a base layer; and a back layer, in which a surface on a side of the magnetic layer has a kurtosis of 3.0 or more, a surface on a side of the back layer has a kurtosis of 2.0 or more, the surface on the magnetic layer side has arithmetic average roughness Ra of 2.5 nm or less, the base layer includes a polyester as a main component, the magnetic recording medium has an average thickness tT of 5.6 μm or less, the magnetic recording medium includes a lubricant, the lubricant includes a fatty acid and a fatty acid ester, and a mass ratio between the fatty acid and the fatty acid ester extracted with hexane satisfies fatty acid/fatty acid ester≤0.6, and the magnetic recording medium has pores, and the pores have an average diameter of 6 nm or more and 11 nm or less when the diameters of the pores are measured in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried.

公开(公告)号：US11574651B2

公开(公告)日：2023-02-07

申请号：US16477687

申请日：2017-12-28

Applicant: Sony Corporation

Inventor： Masaru Terakawa ,  Yoichi Kanemaki ,  Minoru Yamaga

IPC: G11B5/706 ,  G11B5/712 ,  G11B5/714

Abstract: A magnetic recording medium, which is used in a recording and playback device in which the shortest recording wavelength is 75 nm or less, in which the magnetic recording medium has a recording layer including powder of ε-iron oxide-containing particles, the average particle size of the particles is 22 nm or less, the coercive force He is 220 kA/m or more and 320 kA/m or less, and the non linear transition shift is 20% or less.

公开(公告)号：US11521768B2

公开(公告)日：2022-12-06

申请号：US16496357

申请日：2018-03-30

Applicant: POWDERTECH CO., LTD.

Inventor： Kazutaka Ishii ,  Koji Aga ,  Takao Sugiura ,  Takashi Kojima

IPC: H01F1/11 ,  B29C41/08 ,  G11B5/706 ,  G11B5/714 ,  H01F1/113

Abstract: The ferrite powder of the present invention is a ferrite powder containing a plurality of ferrite particles, wherein the ferrite particles each are a single crystal body having an average particle diameter of 1-2,000 nm, and have a polyhedron shape, and wherein the ferrite particles each contain 2.0-10.0 mass % of Sr, and 55.0-70.0 mass % of Fe.

公开(公告)号：US11508407B2

公开(公告)日：2022-11-22

申请号：US16474437

申请日：2018-11-26

Applicant: Sony Corporation

Inventor： Noboru Sekiguchi ,  Minoru Yamaga

IPC: G11B5/706 ,  G11B5/592 ,  G11B5/714 ,  G11B5/733 ,  G11B5/78

Abstract: A magnetic recording medium is a magnetic recording medium having a tape-like shape and includes a base substrate and a magnetic layer provided on the base substrate. A plurality of data tracks can be formed in the magnetic layer, a width of a data track is 2900 nm or less, and in a case of defining, as wmax and wmin, a maximum value and a minimum value respectively out of average values of a width of the magnetic recording medium measured under four kinds of environment in which temperature and relative humidity are set to (10° C., 10%), (10° C., 80%), (29° C., 80%), and (45° C., 10%), wmax and wmin satisfy a relation of (wmax−wmin)/wmin≤400 [ppm].

公开(公告)号：US11462242B2

公开(公告)日：2022-10-04

申请号：US17326458

申请日：2021-05-21

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 ,  G11B5/733 ,  G11B5/78

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.