公开(公告)号：US20210287709A1

公开(公告)日：2021-09-16

申请号：US17196376

申请日：2021-03-09

Applicant: FUJIFILM Corporation

Inventor： Takashi FUJIMOTO ,  Norihito KASADA ,  Eiki OZAWA

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

Abstract: The magnetic tape includes a non-magnetic support and a magnetic layer including ferromagnetic powder, in which the ferromagnetic powder is ε-iron oxide powder, and a coefficient of variation of particle size of the ε-iron oxide powder in a longitudinal direction of the magnetic layer is more than 5.00% and 15.00% or less.

公开(公告)号：US20210287708A1

公开(公告)日：2021-09-16

申请号：US17196349

申请日：2021-03-09

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA ,  Norihito KASADA ,  Takashi FUJIMOTO

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

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 vertical squareness ratio of the magnetic recording medium measured after pressing the magnetic layer at a pressure of 70 atm is 0.50 to 0.95.

公开(公告)号：US20210287705A1

公开(公告)日：2021-09-16

申请号：US17194968

申请日：2021-03-08

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Eiki OZAWA ,  Takashi FUJIMOTO

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

Abstract: The magnetic recording medium includes a non-magnetic support, and a magnetic layer containing a ferromagnetic powder in which the ferromagnetic powder is ε-iron oxide powder, and an anisotropic magnetic field Hk of the magnetic recording medium measured after pressing the magnetic layer at a pressure of 70 atm is 15,000 Oe to 40,000 Oe.

公开(公告)号：US20210241786A1

公开(公告)日：2021-08-05

申请号：US17160534

申请日：2021-01-28

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Yosuke Sumiya

IPC: G11B5/008 ,  G11B5/706

Abstract: The magnetic tape cartridge includes a magnetic tape that is accommodated in the magnetic tape cartridge while being wound around a reel hub. The magnetic tape has a non-magnetic support and a magnetic layer including ferromagnetic powder, and includes one or more components selected from the group consisting of a fatty acid and a fatty acid amide in a portion on the magnetic layer side on the non-magnetic support, and after the magnetic tape cartridge is stored in an environment of an atmosphere temperature of 60° C. and a relative humidity of 80% for 24 hours, a C—H derived C concentration calculated from a C—H peak area ratio of C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed at a photoelectron take-off angle of 10 degrees on a surface of the magnetic layer in an inner region during winding of the magnetic tape is 45 at % or more.

公开(公告)号：US20210233564A1

公开(公告)日：2021-07-29

申请号：US17155540

申请日：2021-01-22

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA

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

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：US20210082464A1

公开(公告)日：2021-03-18

申请号：US17022919

申请日：2020-09-16

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA ,  Norihito KASADA

IPC: G11B5/706 ,  G11B5/008 ,  G11B5/735

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 less than 3.8.

公开(公告)号：US20200251138A1

公开(公告)日：2020-08-06

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：US20200243111A1

公开(公告)日：2020-07-30

申请号：US16849154

申请日：2020-04-15

Applicant: FUJIFILM Corporation

Inventor： Yusuke KAGAWA ,  Norihito KASADA ,  Yuto MURATA

IPC: G11B5/78 ,  G11B5/73 ,  G11B5/735 ,  G11B5/70 ,  G11B23/107

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 including a ferromagnetic powder and a binding agent on the non-magnetic support, a tape thickness is equal to or smaller than 5.2 μm, a tape width difference (B−A) between a tape width A at a position of 10 m±1 m from a tape outer end and a tape width B at a position of 50 m±1 m from a tape inner end is 2.4 μm to 12.0 μm, and the tape width A and the tape width B are values measured 100 days from the date of magnetic tape cartridge manufacture.

公开(公告)号：US20200211593A1

公开(公告)日：2020-07-02

申请号：US16727205

申请日：2019-12-26

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA

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

Abstract: Provided are a magnetic tape including: a non-magnetic support; a magnetic layer including ferromagnetic powder and a binding agent on one surface side of the non-magnetic support; and a back coating layer including non-magnetic powder and a binding agent on the other surface side of the non-magnetic support, in which an isoelectric point of a surface zeta potential of the magnetic layer is equal to or greater than 5.5, and an isoelectric point of a surface zeta potential of the back coating layer is equal to or greater than 4.5, a magnetic tape cartridge, and a magnetic tape apparatus including this magnetic tape.

公开(公告)号：US20200005828A1

公开(公告)日：2020-01-02

申请号：US16456459

申请日：2019-06-28

Applicant: FUJIFILM Corporation

Inventor： Eiki OZAWA ,  Norihito KASADA ,  Atsushi MUSHA

IPC: G11B20/10 ,  G11B5/008 ,  G11B5/584 ,  G11B5/78

Abstract: A magnetic tape apparatus, in which full widths at half maximum of spacing distribution measured by optical interferometry regarding a surface of a magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and equal to or smaller than 15.0 nm, a difference between spacings measured by optical interferometry regarding the surface of the magnetic layer before and after performing the vacuum heating is greater than 0 nm and equal to or smaller than 12.0 nm, and the 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.