公开(公告)号：US20210082463A1

公开(公告)日：2021-03-18

申请号：US17021529

申请日：2020-09-15

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA ,  Norihito KASADA

IPC: G11B5/706 ,  G11B5/733 ,  G11B5/73 ,  G11B5/008

Abstract: The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder, in which an isoelectric point of a surface zeta potential of the magnetic layer after pressing the magnetic layer at a pressure of 70 atm is equal to or greater than 5.5.

公开(公告)号：US20200005817A1

公开(公告)日：2020-01-02

申请号：US16456745

申请日：2019-06-28

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA ,  Norihito KASADA ,  Atsushi MUSHA

IPC: G11B5/584 ,  G11B5/008

Abstract: A magnetic tape apparatus, in which a magnetic tape includes a servo pattern in a magnetic layer, ΔSFD in a longitudinal direction of the magnetic tape is equal to or smaller than 0.50, a reading element unit includes a plurality of reading elements each of which reads data by a linear scanning method from a specific track region including a reading target track in a track region included in the magnetic tape, an extraction unit performs a waveform equalization process according to a deviation amount between positions of the magnetic tape and the reading element unit, with respect to each reading result for each reading element, to extract data derived from the reading target track from the reading result, and the deviation amount is determined in accordance with a result obtained by reading of the servo pattern included in the magnetic layer of the magnetic tape by a servo element.

公开(公告)号：US20190304497A1

公开(公告)日：2019-10-03

申请号：US16367918

申请日：2019-03-28

Applicant: FUJIFILM Corporation

Inventor： Takuto KUROKAWA ,  Eiki OZAWA

IPC: G11B5/706 ,  G11B5/78 ,  G11B5/127

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 a center line average surface roughness Ra measured regarding a surface of the magnetic layer is 1.0 nm to 1.6 nm, and a difference (Safter−Sbefore) between a spacing Safter measured by optical interferometry regarding the surface of the magnetic layer after ethanol cleaning and a spacing Sbefore measured by optical interferometry regarding the surface of the magnetic layer before ethanol cleaning is greater than 0 nm and equal to or smaller than 6.0 nm.

公开(公告)号：US20190103134A1

公开(公告)日：2019-04-04

申请号：US16142560

申请日：2018-09-26

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Eiki OZAWA

IPC: G11B5/72 ,  G11B5/008 ,  G11B5/708 ,  G11B5/706

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 coefficient of friction measured regarding a base portion of a surface of the magnetic layer is equal to or smaller than 0.30, 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.

公开(公告)号：US20190103131A1

公开(公告)日：2019-04-04

申请号：US16144428

申请日：2018-09-27

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Eiki OZAWA

IPC: G11B5/008 ,  G11B5/706 ,  G11B5/39 ,  G11B5/48 ,  G11B5/735 ,  G11B5/84 ,  G11B15/18

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.

公开(公告)号：US20190096436A1

公开(公告)日：2019-03-28

申请号：US16121799

申请日：2018-09-05

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA

IPC: G11B5/584

Abstract: Provided is a magnetic recording medium, which is a magnetic recording medium for microwave-assisted recording and 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 shows a natural ferromagnetic resonance frequency equal to or greater than 30.0 GHz and an anisotropic magnetic field distribution equal to or smaller than 35%.

公开(公告)号：US20190027182A1

公开(公告)日：2019-01-24

申请号：US16037520

申请日：2018-07-17

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA

IPC: G11B5/84 ,  G11B5/702

Abstract: Provided is a manufacturing method of a magnetic recording medium, in which the magnetic recording medium includes a magnetic layer including ferromagnetic powder and a binding agent on a non-magnetic support, and the magnetic layer shows a natural ferromagnetic resonance frequency equal to or greater than 30.0 GHz, the method including: forming a servo pattern on the magnetic layer by microwave-assisted recording.

公开(公告)号：US20180286443A1

公开(公告)日：2018-10-04

申请号：US15920616

申请日：2018-03-14

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA ,  Norihito KASADA

IPC: G11B5/706 ,  G11B5/008

CPC classification number: G11B5/70615 ,  G11B5/00813 ,  G11B5/70 ,  G11B5/70626 ,  G11B5/71 ,  G11B5/78

Abstract: The magnetic tape has the total thickness of a non-magnetic layer and a magnetic layer of 0.60 μm or smaller, the magnetic layer including an abrasive and fatty acid ester, a percentage of a plan view maximum area of the abrasive confirmed in a region having a size of 4.3 μm×6.3 μm of the surface of the magnetic layer with respect to the total area of the region, obtained by plane observation performed by using an SEM of 0.02% or greater and less than 0.06%, full widths at half maximum of spacing distribution measured by optical interferometry regarding a surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape of greater than 0 nm and 7.0 nm or smaller, and a difference between spacings before and after the vacuum heating of greater than 0 nm and 8.0 nm or smaller.

公开(公告)号：US20180240489A1

公开(公告)日：2018-08-23

申请号：US15900080

申请日：2018-02-20

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Eiki OZAWA

IPC: G11B5/70 ,  G11B5/008 ,  G11B5/39

CPC classification number: G11B5/70 ,  G11B5/00813 ,  G11B5/3906 ,  G11B5/3909 ,  G11B5/59633 ,  G11B5/68 ,  G11B5/706 ,  G11B5/74 ,  G11B5/78

Abstract: The magnetic tape device including: a magnetic tape including a servo pattern on a magnetic layer; and a TMR head as a servo head, in which a center line average surface roughness Ra measured regarding a surface of the magnetic layer of the magnetic tape is equal to or smaller than 2.0 nm, a logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is equal to or smaller than 0.050, and ΔSFD in a longitudinal direction of the magnetic tape calculated by Expression 1: ΔSFD=SFD25° C.−SFD−190° C. is equal to or smaller than 0.50, wherein the SFD25° C. is SFD measured in a longitudinal direction of the magnetic tape at a temperature of 25° C., and the SFD−190° C. is SFD measured in a longitudinal direction of the magnetic tape at a temperature of −190° C.

公开(公告)号：US20170372744A1

公开(公告)日：2017-12-28

申请号：US15626832

申请日：2017-06-19

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA ,  Tetsuya KANEKO ,  Norihito KASADA

IPC: G11B5/78 ,  G11B5/71 ,  G11B5/708 ,  G11B5/73 ,  G11B5/584

Abstract: Provided is a magnetic tape in which the total thickness of a non-magnetic layer and a magnetic layer is equal to or smaller than 0.60 μm, the magnetic layer includes a timing-based servo pattern, the magnetic layer includes fatty acid ester, a full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the magnetic layer before performing vacuum heating with respect to the magnetic tape is greater than 0 nm and equal to or smaller than 7.0 nm, a full width at half maximum of spacing distribution measured after performing the vacuum heating is greater than 0 nm and equal to or smaller than 7.0 nm, and a difference between a spacing measured after performing the vacuum heating and a spacing measured before performing the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm.