公开(公告)号：US20190027167A1

公开(公告)日：2019-01-24

申请号：US16038669

申请日：2018-07-18

Applicant: FUJIFILM Corporation

Inventor： Toshio TADA ,  Norihito KASADA ,  Eiki OZAWA ,  Takuto KUROKAWA

IPC: G11B5/008 ,  G11B5/78 ,  G11B5/706 ,  G11B5/712 ,  G11B5/708 ,  G11B5/84

Abstract: The magnetic recording medium includes a non-magnetic support and a magnetic layer, wherein the magnetic layer contains ferromagnetic hexagonal ferrite powder and an abrasive, Int (110)/Int (114) of a crystal structure of the hexagonal ferrite determined by performing XRD analysis on the magnetic layer by using an In-Plane method is equal to or higher than 0.5 and equal to or lower than 4.0, a squareness ratio of the magnetic recording medium in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00, one or more kinds of components selected from the group consisting of a fatty acid and a fatty acid amide is contained in a magnetic layer side portion on the support, and a C—H-derived C concentration obtained by ESCA within a surface of the magnetic layer at a photoelectron take-off angle of 10° is equal to or higher than 45 at %.

公开(公告)号：US20180301165A1

公开(公告)日：2018-10-18

申请号：US16012018

申请日：2018-06-19

Applicant: FUJIFILM Corporation

Inventor： Masahito OYANAGI ,  Norihito KASADA ,  Toshio TADA ,  Takuro SUGIYAMA

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

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：US20170053670A1

公开(公告)日：2017-02-23

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

CPC classification number: G11B5/78 ,  G11B5/70 ,  G11B5/7085 ,  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.

Abstract translation: 磁带具有在非磁性载体上含有铁磁粉末和粘合剂的磁性层，其中在磁带的磁性层一侧的表面上测量的中心线平均表面粗糙度Ra小于或等于1.8nm，而对数 通过在磁带的磁性层一侧的表面上的摆式粘弹性测试确定的减量小于或等于0.050。

公开(公告)号：US20160217817A1

公开(公告)日：2016-07-28

申请号：US15002599

申请日：2016-01-21

Applicant: DOWA ELECTRONICS MATERIALS CO., LTD. ,  FUJIFILM Corporation

Inventor： Kenji MASADA ,  Hirohisa OMOTO ,  Futoshi NAGASHIMA ,  Hiroyuki SUZUKI ,  Toshio TADA

IPC: G11B5/72

CPC classification number: G11B5/70678 ,  H01F1/11

Abstract: A hexagonal ferrite magnetic powder for a magnetic recording medium, containing magnetic powder contains hexagonal ferrite particles having coated on the surface thereof an aluminum hydroxide material, having a Ba/Fe molar ratio of 0.080 or more, a Bi/Fe molar ratio of 0.025 or more, and an Al/Fe molar ratio of from 0.030 to 0.200. The magnetic powder preferably has an activation volume Vact of from 1,300 to 2,000 nm3. The magnetic powder particularly preferably has a coercive force Hc of from 159 to 287 kA/m (approximately from 2,000 to 3,600 Oe) and a coercivity distribution SFD of from 0.3 to 1.0. The magnetic powder may contain one or two or more kinds of a divalent transition metal M1 and a tetravalent transition metal M2, as an element that replaces Fe of the hexagonal ferrite. The magnetic powder has improved magnetic characteristics including SNR and durability.

Abstract translation: 含有磁性粉末的磁记录介质的六方晶系铁氧体磁粉包含六方晶系铁氧体颗粒，其表面上涂有BaO / Fe摩尔比为0.080以上，Bi / Fe摩尔比为0.025或 更多，Al / Fe摩尔比为0.030〜0.200。 磁性粉末的活化体积V act优选为1300〜2000nm 3。 磁性粉末特别优选具有159至287kA / m（约2,000至3600Oe）的矫顽力Hc和0.3至1.0的矫顽力分布SFD。 磁性粉末可以含有一种或两种以上的二价过渡金属M1和四价过渡金属M2，作为取代六方晶系铁氧体的Fe的元素。 磁粉具有改善的磁特性，包括SNR和耐久性。

公开(公告)号：US20160093322A1

公开(公告)日：2016-03-31

申请号：US14867752

申请日：2015-09-28

Applicant: FUJIFILM Corporation

Inventor： Norihito KASADA ,  Masahito OYANAGI ,  Toshio TADA ,  Yasuhiro KAWATANI

IPC: G11B5/708 ,  G11B5/70

CPC classification number: G11B5/708 ,  G11B5/70

Abstract: The magnetic tape comprises, on a nonmagnetic support, a nonmagnetic layer comprising nonmagnetic powder and binder, and on the nonmagnetic layer, a magnetic layer comprising ferromagnetic powder, nonmagnetic powder, and binder, wherein a total thickness of the magnetic tape is less than or equal to 4.80 μm, and a coefficient of friction as measured on a base portion of a surface of the magnetic layer is less than or equal to 0.35.

Abstract translation: 该磁带在非磁性载体上包含非磁性粉末和粘合剂的非磁性层，并且在非磁性层上包括含有铁磁粉末，非磁性粉末和粘合剂的磁性层，其中磁带的总厚度小于或等于 等于4.80μm，并且在磁性层的表面的基部上测量的摩擦系数小于或等于0.35。

公开(公告)号：US20140295214A1

公开(公告)日：2014-10-02

申请号：US14224726

申请日：2014-03-25

Applicant: FUJIFILM CORPORATION

Inventor： Toshio TADA ,  Hiroyuki SUZUKI ,  Osamu SHIMIZU

IPC: H01F1/11 ,  G11B5/706

CPC classification number: H01F1/11 ,  G11B5/70615 ,  G11B5/70678

Abstract: Hexagonal ferrite magnetic particles have an activation volume ranging from 1,000 nm3 to 1,500 nm3, and ΔE10%/kT, thermal stability at 10% magnetization reversal, is equal to or greater than 40.

Abstract translation: 六角铁氧体磁性颗粒的活化体积为1,000nm 3〜1500nm 3，10％磁化反转时的热稳定性为＆Dgr; E10％/ kT，为40以上。

公开(公告)号：US20140287270A1

公开(公告)日：2014-09-25

申请号：US14223139

申请日：2014-03-24

Applicant: FUJIFILM CORPORATION

Inventor： Hiroyuki SUZUKI ,  Toshio TADA

IPC: G11B5/706

CPC classification number: G11B5/70678 ,  H01F1/11 ,  Y10T428/2982

Abstract: An aspect of the present invention relates to hexagonal ferrite magnetic powder, which has an activation volume ranging from 900 nm3 to 1,600 nm3, and a ratio of a coefficient of plate thickness variation to a coefficient of particle diameter variation, coefficient of plate thickness variation/coefficient of particle diameter coefficient, ranging from 0.20 to 0.60.

Abstract translation: 本发明的一个方面涉及六方晶系铁氧体磁粉，其活性体积范围为900nm 3至1600nm 3，并且板厚变化系数与粒径变化系数之比，板厚变化系数/ 粒径系数系数为0.20〜0.60。