公开(公告)号：US09711174B2

公开(公告)日：2017-07-18

申请号：US14757555

申请日：2015-12-24

Applicant: FUJIFILM CORPORATION

Inventor： Norihito Kasada ,  Masahito Oyanagi ,  Toshio Tada ,  Kazuyuki Kitada

IPC: G11B5/71 ,  G11B5/73 ,  G11B5/84 ,  G11B5/842 ,  G11B5/78

CPC classification number: G11B5/71 ,  G11B5/7305 ,  G11B5/78 ,  G11B5/8404 ,  G11B5/842

Abstract: Provided is a magnetic tape, which comprises, on a nonmagnetic support, a nonmagnetic layer comprising nonmagnetic powder and binder, and on the nonmagnetic layer, a magnetic layer comprising ferromagnetic powder and binder; wherein a total thickness of the magnetic tape is less than or equal to 4.80 μm; at least the magnetic layer comprises 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 magnetic layer side of the magnetic tape is greater than or equal to 45 atom %.

公开(公告)号：US10896692B2

公开(公告)日：2021-01-19

申请号：US15443094

申请日：2017-02-27

Applicant: FUJIFILM Corporation

Inventor： Takuto Kurokawa ,  Norihito Kasada ,  Masahito Oyanagi

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

Abstract: The magnetic tape has a magnetic layer containing ferromagnetic powder and binder on one surface of a nonmagnetic support and has a backcoat layer containing nonmagnetic powder and binder on the other surface thereof, wherein the thickness of the backcoat layer is less than or equal to 0.20 μm, and the contact angle for 1-bromonaphthalene that is measured on the surface of the backcoat layer falls within a range of 10.0° to 30.0°.

公开(公告)号：US10540996B2

公开(公告)日：2020-01-21

申请号：US15280195

申请日：2016-09-29

Applicant: FUJIFILM Corporation

Inventor： Eiki Ozawa ,  Norihito Kasada ,  Masahito Oyanagi ,  Toshio Tada

IPC: G11B5/70 ,  G11B5/708

Abstract: A magnetic tape has a magnetic layer containing ferromagnetic powder and binder on a nonmagnetic support. The magnetic layer contains a fatty acid ester. The full width at half maximum of the spacing distribution as measured by optical interferometry on the magnetic layer side surface of the magnetic tape before vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 5.0 nm. The full width at half maximum of the spacing distribution after vacuum heating the magnetic tape is greater than 0 nm but less than or equal to 5.0 nm. The difference between the spacing Safter after vacuum heating the magnetic tape and the spacing Sbefore before vacuum heating the magnetic tape, Safter−Sbefore, is greater than 0 nm but less than or equal to 8.0 nm.

公开(公告)号：US10475481B2

公开(公告)日：2019-11-12

申请号：US15422821

申请日：2017-02-02

Applicant: FUJIFILM Corporation

Inventor： Masahito Oyanagi ,  Norihito Kasada ,  Eiki Ozawa

IPC: G11B5/73 ,  G11B5/735 ,  G11B5/70 ,  G11B5/733 ,  G11B5/78 ,  G11B5/84 ,  G11B5/008

Abstract: The magnetic tape has a magnetic layer and a backcoat layer. The Ra on the magnetic layer side surface is less than or equal to 1.8 nm, the coefficient of friction measured on the base portion of the magnetic layer side surface is less than or equal to 0.35, and the Ra measured on the backcoat layer side surface is less than or equal to 5.0 nm. The backcoat layer contains a fatty acid ester. In addition, the FWHMbefore measured on the backcoat layer side surface before vacuum heating is greater than 0 nm but less than or equal to 10.0 nm, the FWHMafter after vacuum heating is greater than 0 nm but less than or equal to 10.0 nm, and 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：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：US09601146B2

公开(公告)日：2017-03-21

申请号：US14753227

申请日：2015-06-29

Applicant: FUJIFILM Corporation

Inventor： Norihito Kasada ,  Masahito Oyanagi ,  Toshio Tada

IPC: G11B5/708 ,  G11B5/78 ,  G11B5/70 ,  G11B5/714

CPC classification number: G11B5/78 ,  G11B5/70 ,  G11B5/714

Abstract: An aspect of the present invention relates to a magnetic tape comprising a magnetic layer comprising ferromagnetic powder and binder on a nonmagnetic support, wherein ΔSFD in a longitudinal direction of the magnetic tape as calculated with Equation 1 ranges from 0.35 to 1.50: ΔSFD=SFD25° C.−SFD−190° C.  Equation 1 wherein, in Equation 1, SFD25° C. denotes a switching field distribution SFD as measured in the longitudinal direction of the magnetic tape in an environment with a temperature of 25° C., and SFD−190° C. denotes a switching field distribution SFD as measured in the longitudinal direction of the magnetic tape in an environment with a temperature of −190° C.