Orientation device, production method for magnetic recording medium, and magnetic recording medium

Patent metadata

Field	Value
Publication number	US-2020402533-A1
Application number	US-201916613700-A
Country	US
Kind code	A1
Filing date	Mar 6, 2019
Priority date	Mar 16, 2018
Publication date	Dec 24, 2020
Grant date	—

Abstract

[Solving Means] An orientation device according to the present technology includes a transport path, a permanent magnet portion, and a yoke portion. The transport path allows a base on which a magnetic coating film containing magnetic powder has been formed to pass through the transport path along a transport direction. The permanent magnet portion includes a plurality of first permanent magnets, and a plurality of second permanent magnets that is opposed to the plurality of first permanent magnets across the transport path in a vertical direction that is vertical to the transport direction in a manner that opposite poles face each other, the permanent magnet portion vertically orienting particles of the magnetic powder by applying a magnetic field to the magnetic coating film on the base that passes through the transport path. The yoke portion is made of a soft magnetic material, and connects to poles on a side opposite to the transport path side of the plurality of first permanent magnets, and to poles on a side opposite to the transport path side of the plurality of second permanent magnets.

First claim

1 . An orientation device, comprising:
a transport path that allows a base on which a magnetic coating film containing magnetic powder has been formed to pass through the transport path along a transport direction; a permanent magnet portion that includes
a plurality of first permanent magnets, and
a plurality of second permanent magnets that is opposed to the plurality of first permanent magnets across the transport path in a vertical direction that is vertical to the transport direction in a manner that opposite poles face each other, the permanent magnet portion vertically orienting particles of the magnetic powder by applying a magnetic field to the magnetic coating film on the base that passes through the transport path; and
a yoke portion
that is made of a soft magnetic material, and
that connects
to poles on a side opposite to the transport path side of the plurality of first permanent magnets, and
to poles on a side opposite to the transport path side of the plurality of second permanent magnets.

2 . The orientation device according to claim 1 , wherein
a vertical component of the magnetic field in the transport path is 1.0 time or more as large as a coercive force of the magnetic coating film.

3 . The orientation device according to claim 1 , wherein
the yoke portion includes
a first yoke portion that supports the plurality of first permanent magnets from the side opposite to the transport path side of the plurality of first permanent magnets,
a second yoke portion that supports the plurality of second permanent magnets from the side opposite to the transport path side of the plurality of second permanent magnets, and
third yoke portions that couple the first yoke portion and the second yoke portion to each other.

4 . The orientation device according to claim 3 , wherein
a relationship Bmag×Wm<Byoke×2T is satisfied, where
T is a smallest thickness of
a thickness in the vertical direction of the first yoke portion,
a thickness in the vertical direction of the second yoke portion, and
a thickness in a width direction of each of the third yoke portions, the width direction being a direction orthogonal to the transport direction and the vertical direction,

Bmag is a remanent magnetic-flux density of the plurality of first permanent magnets and the plurality of second permanent magnets,
Wm is a width of each of the plurality of first permanent magnets and the plurality of second permanent magnets, and
Byoke is a saturation magnetic-flux density of the yoke portion.

5 . The orientation device according to claim 1 , further comprising:
a drying portion that dries the magnetic-layer coating film under a state in which the particles of the magnetic powder in the magnetic-layer coating film have been vertically oriented by the magnetic field applied from the permanent magnet portion.

6 . The orientation device according to claim 5 , wherein
the drying portion includes a plurality of blowing ports that allows airflow for drying the magnetic coating film to be blown into the transport path.

7 . The orientation device according to claim 6 , wherein
the orientation device includes, in the transport path,
a first area in which the plurality of blowing ports is not provided in the transport direction, and
a second area in which the plurality of blowing ports is provided in the transport direction.

8 . The orientation device according to claim 7 , wherein
the first area is a part area on an upstream side in the transport direction, and the second area is a part area on a downstream side out of the part area on the upstream side.

9 . The orientation device according to claim 8 , wherein
the plurality of first permanent magnets includes ones of the plurality of first permanent magnets, the ones of the plurality of first permanent magnets being located in the second area, the plurality of second permanent magnets includes ones of the plurality of second permanent magnets, the ones of the plurality of second permanent magnets being located in the second area, both the ones of the plurality of first permanent magnets and the ones of the plurality of second permanent magnets are each arranged at a predetermined gap in the transport direction, and the plurality of blowing ports is provided at positions corresponding to the gap.

10 . The orientation device according to claim 6 , wherein
the drying portion further includes a plurality of suction ports for allowing the airflow in the transport path to be sucked and discharged to an outside of the transport path.

11 . The orientation device according to claim 10 , wherein
the plurality of blowing ports is provided to allow the airflow to be blown in the vertical direction, and the plurality of suction ports is provided to allow the airflow to be sucked in a width direction orthogonal to the transport direction and the vertical direction.

12 . The orientation device according to claim 11 , wherein
each of the plurality of suction ports is provided at an intermediate position in the transport direction between corresponding two of the plurality of blowing ports.

13 . The orientation device according to claim 1 , wherein
the orientation device includes a plurality of units that is thin in the transport direction and arrayed in the transport direction, and each of the plurality of units includes
corresponding one of the plurality of first permanent magnets,
corresponding one of the plurality of second permanent magnets, and
a yoke unit portion that constitutes a part of the yoke portion.

14 . The orientation device according to claim 13 , further comprising:
a magnet fixing plate for fixing the corresponding one of the plurality of first permanent magnet and the corresponding one of the plurality of second permanent magnets to the yoke unit portion, the magnet fixing plate being interposed between ones of the plurality of units, the ones of the plurality of units being adjacent to each other in the transport direction.

15 . The orientation device according to claim 14 , wherein
a thickness of the magnet fixing plate is 2 mm or more and 5 mm or less.

16 . The orientation device according to claim 14 , wherein
the magnet fixing plate includes
a magnetic portion, and
a non-magnetic portion.

17 . The orientation device according to claim 16 , wherein
parts of the magnet fixing plate, the parts corresponding to surfaces vertical to the transport direction of the corresponding one of the plurality of first permanent magnets and of the corresponding one of the plurality of second permanent magnets, are each the non-magnetic portion.

18 . The orientation device according to claim 16 , wherein
the yoke unit includes
a first yoke-unit portion that supports the corresponding one of the plurality of first permanent magnets from the side opposite to the transport path side of the plurality of first permanent magnets,
a second yoke-unit portion that supports the corresponding one of the plurality of second permanent magnets from the side opposite to the transport path side of the plurality of second permanent magnets, and
third yoke-unit portions that couple the first yoke-unit portion and the second yoke-unit portion to each other, and
parts of the magnet fixing plate, the parts corresponding to the third yoke-unit portions, are each the magnetic portion.

19 . A production method for a magnetic recording medium, the production method comprising, in a transport path in an orientation device:
allow

Assignees

• Sony Corp

Inventors

• Nakashio Eiji
• Sakuma Hidetoshi
• Matsuya Shuhei
• Nishiyama Hidetoshi
• Sasaki Jun

Classifications

• G11B5/852

  Orientation in a magnetic field (G11B5/845 takes precedence) · CPC title

• G11B5/78

  Tape carriers · CPC title

• G11B5/70626

  containing non-metallic substances · CPC title

• G11B5/68

  comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent · CPC title

• G11B5/845 Primary

  in a magnetic field · CPC title