公开(公告)号：US12131762B2

公开(公告)日：2024-10-29

申请号：US17955137

申请日：2022-09-28

申请人： FUJIFILM Corporation

发明人： Takashi Fujimoto ,  Eiki Ozawa

IPC分类号： G11B5/706 ,  G11B5/714 ,  G11B5/735

CPC分类号： G11B5/70642 ,  G11B5/714 ,  G11B5/7356

摘要： A magnetic recording medium including a magnetic layer including a ferromagnetic powder. The ferromagnetic powder is an ε-iron oxide powder, and a ratio of Hr (45°) to Hr (0°) (Hr (45°)/Hr (0°)) is 0.50 or less. The Hr (0°) is a residual coercive force Hr obtained by applying a pulse magnetic field having a pulse width of 0.76 ms in an in-plane direction of the magnetic recording medium, and the Hr (45°) is a residual coercive force Hr obtained by setting an angle of the magnetic recording medium in the in-plane direction to 0°, setting an angle of the magnetic recording medium in a perpendicular direction to 90°, and making a pulse magnetic field having a pulse width of 0.76 ms be incident from a direction inclined by 45° toward the perpendicular direction from the in-plane direction and applying the pulse magnetic field to the magnetic recording medium.

公开(公告)号：US20230352045A1

公开(公告)日：2023-11-02

申请号：US18298130

申请日：2023-04-10

申请人： FUJIFILM Corporation

发明人： Yuto MURATA ,  Norihito Kasada ,  Nagisa Yamasaki

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

CPC分类号： G11B5/70678 ,  G11B5/7356 ,  G11B5/5928 ,  G11B5/714

摘要： The magnetic tape includes: a non-magnetic support; and a magnetic layer containing a ferromagnetic powder, in which a non-linear component of a signal phase difference generated by storage for 10 days in an environment of a temperature of 60° C. and a relative humidity of 20% is 17.5 nm or less. A magnetic tape cartridge and a magnetic tape apparatus include the magnetic tape.

公开(公告)号：US11804243B2

公开(公告)日：2023-10-31

申请号：US16649403

申请日：2019-10-18

申请人： Sony Group Corporation

发明人： Minoru Yamaga ,  Noboru Sekiguchi

IPC分类号： G11B5/78 ,  G11B5/706 ,  G11B5/735 ,  G11B5/592 ,  G11B5/712 ,  G11B5/714

CPC分类号： G11B5/70678 ,  G11B5/5928 ,  G11B5/712 ,  G11B5/714 ,  G11B5/7356 ,  G11B5/78

摘要： It is an object of the present technology to provide a magnetic recording medium that has a small total thickness and achieves excellent travelling stability.
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 servo pattern is recorded in the magnetic layer, a statistical value σSW indicating non-linearity of a servo band and being obtained from a reproduction waveform of a servo signal of the servo pattern is 24 nm or less, the base layer contains polyester as a main component, an average thickness tT of the magnetic recording medium is 5.6 μm or less, the magnetic recording medium contains a lubricant, pores are formed in the magnetic recording medium, and an average diameter of the pores of the magnetic recording medium that is measured in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried, is 6 nm or more and 11 nm or less.

公开(公告)号：US20230290375A1

公开(公告)日：2023-09-14

申请号：US18182437

申请日：2023-03-13

申请人： FUJIFILM Corporation

发明人： Eiki OZAWA ,  Takashi FUJIMOTO

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

CPC分类号： G11B5/70642 ,  G11B5/714 ,  G11B5/7356 ,  G11B5/00813

摘要： The magnetic recording medium includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. A magnetic tape cartridge and a magnetic recording and reproducing device include the magnetic recording medium. The ferromagnetic powder is an ε-iron oxide powder, and a ferromagnetic powder filling rate of a magnetic layer cross section obtained by observing a cross section of the magnetic layer with a scanning electron microscope is 0.60 or more and 0.80 or less.

公开(公告)号：US11749305B2

公开(公告)日：2023-09-05

申请号：US16649206

申请日：2019-10-18

申请人： Sony Group Corporation

发明人： Minoru Yamaga ,  Kazuya Hashimoto

IPC分类号： G11B5/71 ,  G11B5/66 ,  G11B5/714

CPC分类号： G11B5/71 ,  G11B5/674 ,  G11B5/714

摘要： To provide a magnetic recording medium that has excellent traveling stability in spite of having a thin total thickness and a thin thickness of an underlayer, and is suitable for use in a recording/reproducing device for adjusting the width of the magnetic recording medium by adjusting a tension of the magnetic recording medium in a longitudinal direction thereof.
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 the underlayer has a thickness of 0.5 μm or more and 0.9 μm or less, the magnetic recording medium has an average thickness tT of 5.6 μm or less, the magnetic recording medium includes a lubricant, 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, and the Young's modulus in a longitudinal direction is 7.90 GPa or less.

公开(公告)号：US20230274764A1

公开(公告)日：2023-08-31

申请号：US18123510

申请日：2023-03-20

申请人： Sony Corporation

发明人： Minoru YAMAGA ,  Futoshi SASAKI

IPC分类号： G11B5/706 ,  G11B5/73 ,  G11B5/735 ,  G11B5/592 ,  G11B5/71 ,  G11B5/714

CPC分类号： G11B5/70678 ,  G11B5/73927 ,  G11B5/7358 ,  G11B5/5928 ,  G11B5/71 ,  G11B5/714

摘要： A magnetic recording medium is a magnetic recording medium in the form of a tape and includes a substrate, a foundation layer provided on the substrate, and a magnetic layer provided on the foundation layer and containing a magnetic powder. The foundation layer and the magnetic layer each contain a lubricant. A squareness ratio of the magnetic layer in a perpendicular direction is equal to or higher than 65%, an average thickness of the magnetic recording medium is equal to or smaller than 5.6 μm, a plurality of recessed portions each having a depth corresponding to 20% or higher of the average thickness of the magnetic layer is provided on a surface of the magnetic layer, and the number of the recessed portions per unit area of 1,600 μm2 of the surface of the magnetic layer is equal to or greater than 20 and equal to or smaller than 200, and an amount of exudation of the lubricant per unit region of 12.5 μm×9.3 μm on the surface of the magnetic layer in a vacuum is equal to or greater than 3.0 μm2 and equal to or smaller than 6.5 μm2.

公开(公告)号：US11705155B2

公开(公告)日：2023-07-18

申请号：US17582158

申请日：2022-01-24

申请人： FUJIFILM Corporation

发明人： Shinji Tsujimoto

IPC分类号： G11B5/68 ,  G11B5/735 ,  G11B5/706 ,  G11B5/714

CPC分类号： G11B5/68 ,  G11B5/70678 ,  G11B5/714 ,  G11B5/7356 ,  G11B5/7358

摘要： The magnetic tape includes a non-magnetic support, a magnetic layer that includes ferromagnetic powder having an average particle volume of 2,500 nm3 or less on one surface side of the non-magnetic support, and a back coating layer that includes non-magnetic powder on the other surface side of the non-magnetic support, in which the ferromagnetic powder is ferromagnetic powder selected from the group consisting of hexagonal ferrite powder and ε-iron oxide powder, and a ratio (PSD5μm-PSDmag/PSD10μm-PSDbc) of the magnetic layer and the back coating layer is in a range of 0.0050 to 0.20. A magnetic tape cartridge and a magnetic recording and reproducing apparatus include the magnetic tape.

公开(公告)号：US11676637B2

公开(公告)日：2023-06-13

申请号：US17366039

申请日：2021-07-02

申请人： FUJIFILM Corporation

发明人： Norihito Kasada ,  Yusuke Kagawa

IPC分类号： G11B5/78 ,  G11B23/107 ,  G11B5/592 ,  G11B15/43 ,  G11B5/735 ,  G11B5/714 ,  G11B5/706 ,  G11B5/73 ,  G11B5/733

CPC分类号： G11B23/107 ,  G11B5/5928 ,  G11B5/70678 ,  G11B5/714 ,  G11B5/73 ,  G11B5/733 ,  G11B5/7356 ,  G11B5/73927 ,  G11B5/78 ,  G11B15/43

摘要： The magnetic tape cartridge includes a magnetic tape, and a cartridge reel. In the magnetic tape, a minimum winding deviation occurrence load measured after the magnetic tape is rewound around the cartridge reel by applying a tension of 0.40 N in a longitudinal direction of the magnetic tape is 300 N or less.

公开(公告)号：US20180182422A1

公开(公告)日：2018-06-28

申请号：US15855412

申请日：2017-12-27

申请人： Maxell Holdings, Ltd.

发明人： Shinji KAWAKAMI ,  Toshio HIROI ,  Masao FUJITA

IPC分类号： G11B5/714 ,  G11B5/706

CPC分类号： G11B5/714 ,  G11B5/70 ,  G11B5/70615 ,  G11B5/70642

摘要： In a magnetic recording medium according to the present invention, if a straight line W having a length of 500 nm and a width of 15 nm is displayed parallel to a width direction of the magnetic layer and a straight line L having a length of 500 nm and a width of 15 nm is displayed parallel to a longitudinal direction of the magnetic layer, the number of magnetic particles that intersect the straight line W is N1, and the number of magnetic particles that intersect the straight line L is N2, then, a relationship of N1/0.5>60 and N2/0.5>60 is established where N1/0.5 is the number of magnetic particles per micrometer obtained by dividing N1 by 0.5 μm and N2/0.5 is the number of magnetic particles per micrometer obtained by dividing N2 by 0.5 μm.

公开(公告)号：US09934809B2

公开(公告)日：2018-04-03

申请号：US15079206

申请日：2016-03-24

申请人： FUJIFILM Corporation

发明人： Toshihide Aoshima ,  Reiko Inushima ,  Mika Imamura ,  Tatsuo Mikami

IPC分类号： G11B5/702 ,  G11B5/70 ,  G11B5/714

CPC分类号： G11B5/7013 ,  G11B5/7028 ,  G11B5/714

摘要： The magnetic recording medium composition contains ferromagnetic powder, binder, and a crosslinkable component selected from the group consisting of a component capable of forming a crosslinking structure by a radical reaction, a component capable of forming a crosslinking structure by an ionic reaction, and a component capable of forming a crosslinking structure by a pericyclic reaction, wherein the crosslinkable component contains at least polyester, and the polyester has a weight average molecular weight ranging from 1,000 to 20,000, as well as contains, per molecule, one or more acidic groups, and one or more reactive groups selected from the group consisting of a radical reactive group, an ionic reactive group, and a pericyclic reactive group.