公开(公告)号：US10475480B2

公开(公告)日：2019-11-12

申请号：US15900242

申请日：2018-02-20

Applicant: FUJIFILM Corporation

Inventor： Takuto Kurokawa ,  Norihito Kasada

IPC: G11B5/71 ,  G11B5/712 ,  G11B5/706 ,  G11B5/008 ,  G11B5/735 ,  G11B5/70 ,  G11B5/702

Abstract: A 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. The center line average surface roughness Ra measured regarding a surface of the magnetic layer is less than or equal to 1.8 nm. The contact angle with respect to 1-bromonaphthalene measured regarding the surface of the magnetic layer is 45.0° to 55.0°. Also, the logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the back coating layer is less than or equal to 0.060.

公开(公告)号：US10453488B2

公开(公告)日：2019-10-22

申请号：US15900379

申请日：2018-02-20

Applicant: FUJIFILM Corporation

Inventor： Takuto Kurokawa ,  Norihito Kasada

IPC: G11B5/71 ,  G11B5/702 ,  C08L75/04 ,  G11B5/70 ,  G11B5/73 ,  G11B5/708 ,  C08G18/79 ,  C08K3/20 ,  G11B5/706

Abstract: A magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support. The center line average surface roughness Ra measured regarding the surface of the magnetic layer is less than or equal to 1.8 nm. The logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is less than or equal to 0.050, and the contact angle with respect to 1-bromonaphthalene measured regarding the surface of the magnetic layer is 45.0° to 55.0°.

公开(公告)号：US10438624B2

公开(公告)日：2019-10-08

申请号：US15900106

申请日：2018-02-20

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/71 ,  G11B5/008 ,  G11B5/73 ,  G11B5/588 ,  G11B5/708 ,  G11B5/70 ,  G11B5/706 ,  G11B5/78 ,  G11B5/845

Abstract: A magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support. The center line average surface roughness Ra measured regarding the surface of the magnetic layer is less than or equal to 1.8 nm. The logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the magnetic layer is less than or equal to 0.050. The ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer includes an abrasive, and the tilt cos θ of the ferromagnetic hexagonal ferrite powder with respect to the surface of the magnetic layer acquired by cross section observation performed using a scanning transmission electron microscope is 0.85 to 1.00.

公开(公告)号：US10424330B2

公开(公告)日：2019-09-24

申请号：US15900164

申请日：2018-02-20

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/735 ,  G11B5/712 ,  G11B5/708 ,  G11B5/78

Abstract: A magnetic tape includes a back coating layer having a thickness less than or equal to 0.30 μm and containing fatty acid ester. The logarithmic decrement acquired by a pendulum viscoelasticity test performed regarding the surface of the back coating layer is less than or equal to 0.060. The full width at half maximum of spacing distribution measured by optical interferometry regarding the surface of the back coating layer before and after performing a vacuum heating with respect to the magnetic tape is respectively greater than 0 nm and less than or equal to 10.0 nm, and the difference between the spacing measured by optical interferometry regarding the surface of the back coating layer after performing the vacuum heating and the spacing measured before performing the vacuum heating is greater than 0 nm and less than or equal to 8.0 nm.

公开(公告)号：US10410665B2

公开(公告)日：2019-09-10

申请号：US15920515

申请日：2018-03-14

Applicant: FUJIFILM Corporation

Inventor： Eiki Ozawa ,  Norihito Kasada

IPC: G11B5/714 ,  G11B5/706 ,  G11B5/008 ,  G11B5/70 ,  G11B5/39 ,  G11B5/78

Abstract: The magnetic tape device includes a TMR head (reproducing head); and a magnetic tape including a magnetic layer including ferromagnetic hexagonal ferrite powder, a binding agent, and fatty acid ester, in which an XRD intensity ratio 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 direction squareness ratio is 0.65 to 1.00, Ra measured regarding a surface of the magnetic layer is equal to or smaller than 2.0 nm, full widths at half maximum of spacing distribution measured by optical interferometry regarding the surface of the 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 7.0 nm, and a difference between spacings before and after the vacuum heating is greater than 0 nm and equal to or smaller than 8.0 nm.

公开(公告)号：US10347279B2

公开(公告)日：2019-07-09

申请号：US15422944

申请日：2017-02-02

Applicant: FUJIFILM Corporation

Inventor： Eiki Ozawa ,  Masahito Oyanagi ,  Norihito Kasada

IPC: G11B5/73 ,  G11B5/735 ,  G11B5/70 ,  G11B5/733 ,  G11B5/84 ,  G11B5/78

Abstract: A magnetic tape has a magnetic layer and a backcoat layer. Each of the magnetic layer and the backcoat layer contains a fatty acid ester. The Ra measured on the magnetic layer side surface is less than or equal to 2.8 nm. The difference between the spacing measured by optical interferometry on the magnetic layer side surface after and before vacuum heating is greater than 0 nm but less than or equal to 8.0 nm. The FWHMbefore on the backcoat layer side surface is greater than 0 nm but less than or equal to 10.0 nm. The FWHMafter on the backcoat layer side surface is greater than 0 nm but less than or equal to 10.0 nm. The difference between the spacing measured on the backcoat layer side surface after and before vacuum heating is greater than 0 nm but less than or equal to 8.0 nm.

公开(公告)号：US10026435B2

公开(公告)日：2018-07-17

申请号：US15241631

申请日：2016-08-19

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Masahito Oyanagi ,  Toshio Tada ,  Takuro Sugiyama

IPC: G11B5/78 ,  G11B5/70 ,  G11B5/735 ,  G11B5/842

Abstract: The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on the surface on one side of a nonmagnetic support and has a backcoat layer containing nonmagnetic powder and binder on the surface on the other side of the nonmagnetic support, wherein the backcoat layer is less than or equal to 0.30 μm in thickness; and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the backcoat layer side of the magnetic tape is less than or equal to 0.060.

公开(公告)号：US10026434B2

公开(公告)日：2018-07-17

申请号：US15241297

申请日：2016-08-19

Applicant: FUJIFILM Corporation

Inventor： Masahito Oyanagi ,  Norihito Kasada ,  Toshio Tada ,  Takuro Sugiyama

IPC: G11B5/78 ,  G11B5/70 ,  G11B5/708 ,  G11B5/842

Abstract: The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support, wherein the centerline average surface roughness Ra as measured on the surface on the magnetic layer side of the magnetic tape is less than or equal to 1.8 nm, and the logarithmic decrement as determined by a pendulum viscoelasticity test on the surface on the magnetic layer side of the magnetic tape is less than or equal to 0.050.

公开(公告)号：US10008230B1

公开(公告)日：2018-06-26

申请号：US15854506

申请日：2017-12-26

Applicant: FUJIFILM Corporation

Inventor： Eiki Ozawa ,  Tetsuya Kaneko ,  Norihito Kasada

IPC: G11B5/84 ,  G11B5/39 ,  G11B5/71 ,  G11B5/725

Abstract: The magnetic tape device includes: a magnetic tape; and a servo head, in which the servo head is a TMR head, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder, a binding agent, and fatty acid ester on the non-magnetic support, the magnetic layer includes a servo pattern, 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 are greater than 0 nm and equal to or smaller than 7.0 nm, and a difference between a spacing measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape and a spacing measured before performing the vacuum heating is greater than 0 nm and equal to or smaller than 9.0 nm.

公开(公告)号：US09704527B2

公开(公告)日：2017-07-11

申请号：US15052115

申请日：2016-02-24

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada

IPC: G11B5/735 ,  G11B5/706 ,  G11B5/70 ,  G11B5/84

CPC classification number: G11B5/735 ,  G11B5/70 ,  G11B5/70605 ,  G11B5/8404

Abstract: The magnetic tape has on one surface of a nonmagnetic support a magnetic layer containing ferromagnetic powder and binder, and on the other surface of the nonmagnetic support, a backcoat layer containing nonmagnetic powder and binder, wherein the total thickness of the magnetic tape is less than or equal to 4.80 μm, the backcoat layer contains one or more components selected from the group consisting of a fatty acid and a fatty acid amide, and a C—H derived carbon, C, concentration calculated from a C—H peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on a surface on the backcoat layer side of the magnetic tape ranges from 35 to 60 atom %.