公开(公告)号：US20220020392A1

公开(公告)日：2022-01-20

申请号：US17376164

申请日：2021-07-15

Applicant: FUJIFILM Corporation

Inventor： Takuto KUROKAWA ,  So MATSUYAMA ,  Norihito KASADA

IPC: G11B5/706 ,  G11B5/735 ,  G11B5/714 ,  G11B5/592

Abstract: The magnetic tape includes a non-magnetic support and a magnetic layer including a ferromagnetic powder, in which in an environment of a temperature of 32° C. and a relative humidity of 80%, a frictional force F0.2 N on a magnetic layer surface with respect to an LTO8 head, which is measured by applying a tension of 0.2 N in a longitudinal direction of the magnetic tape, is in a range of 4 to 15 gf, and a frictional force F1.5 N on the magnetic layer surface with respect to the LTO8 head, which is measured by applying a tension of 1.5 N in the longitudinal direction of the magnetic tape, is in a range of 4 to 15 gf.

公开(公告)号：US20220005503A1

公开(公告)日：2022-01-06

申请号：US17476565

申请日：2021-09-16

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Akinori SUGISHIMA

IPC: G11B5/702

Abstract: The magnetic recording medium includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which an isoelectric point of a surface zeta potential of the magnetic layer is equal to or smaller than 3.8.

公开(公告)号：US20210295865A1

公开(公告)日：2021-09-23

申请号：US17330680

申请日：2021-05-26

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Eiki OZAWA ,  Atsushi MUSHA

IPC: G11B5/584 ,  G11B5/708 ,  G11B5/70 ,  G11B5/702 ,  G11B5/706 ,  G11B5/78 ,  G11B20/10 ,  G11B27/022

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 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 absolute value ΔN of a difference between a refractive index Nxy of the magnetic layer, measured in an in-plane direction and a refractive index Nz of the magnetic layer, measured in a thickness direction is 0.25 or more and 0.40 or less.

公开(公告)号：US20210287707A1

公开(公告)日：2021-09-16

申请号：US17196296

申请日：2021-03-09

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Eiki OZAWA ,  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 c-iron oxide powder, and a coercivity of a magnetic recording medium in a vertical direction measured after pressing the magnetic layer at a pressure of 70 atm is 3,000 Oe to 10,000 Oe.

公开(公告)号：US20210241792A1

公开(公告)日：2021-08-05

申请号：US17160535

申请日：2021-01-28

Applicant: FUJIFILM Corporation

Inventor： Takuto KUROKAWA ,  Naoki SANO ,  Norihito KASADA

IPC: G11B5/706 ,  G11B5/58 ,  G11B5/008 ,  G11B5/735 ,  G11B5/714

Abstract: The magnetic tape in which a difference (S0.1−S1.6) between a spacing S0.1 and a spacing S1.6 obtained after n-hexane cleaning on a surface of the magnetic layer is equal to or less than 32 nm. The S0.1 is a value obtained as a spacing under a pressing force of 0.1 atm from a relational expression between a pressure and a spacing obtained by performing a spacing measurement on the surface of the magnetic layer by an optical interference method under a pressing force of each of a plurality of different pressures after the n-hexane cleaning, and S1.6 is a spacing measured on the surface of the magnetic layer by the optical interference method under the pressing force of 1.6 atm after the n-hexane cleaning.

公开(公告)号：US20210233562A1

公开(公告)日：2021-07-29

申请号：US17154002

申请日：2021-01-21

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：US20210090599A1

公开(公告)日：2021-03-25

申请号：US17022886

申请日：2020-09-16

Applicant: FUJIFILM Corporation

Inventor： Megumi NAKANO ,  Eiki OZAWA ,  Norihito KASADA

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

Abstract: The magnetic recording medium includes a non-magnetic support; and a magnetic layer including a ferromagnetic powder, in which one or more kinds of component selected from the group consisting of a fatty acid and a fatty acid amide are included in a portion of the magnetic layer side on the non-magnetic support, and a C—H derived C concentration calculated from a C—H peak surface area ratio in C1s spectra obtained by X-ray photoelectron spectroscopic analysis performed on a surface of the magnetic layer at a photoelectron take-off angle of 10 degrees, after pressing the magnetic layer at a pressure of 70 atm is 45 atom % or more.

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：US20210020195A1

公开(公告)日：2021-01-21

申请号：US17032621

申请日：2020-09-25

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA

IPC: G11B5/584 ,  G11B5/627 ,  G11B5/008 ,  G11B5/55 ,  G11B5/70 ,  G11B5/706 ,  G11B5/702

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 the magnetic layer has a servo pattern, and 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, a magnetic tape cartridge and a magnetic tape apparatus including this magnetic tape.

公开(公告)号：US20200035267A1

公开(公告)日：2020-01-30

申请号：US16522806

申请日：2019-07-26

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA

IPC: G11B5/706 ,  H01F1/08

Abstract: The magnetic tape includes 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 smaller than 3.8, and an isoelectric point of a surface zeta potential of the back coating layer is equal to or smaller than 3.0, a magnetic tape cartridge, and a magnetic tape apparatus including this magnetic tape.