US4222084A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head
Assignee: TDK Corp
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Filing: 1978-06-14
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Granted: 1980-09-09
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Expires: 1998-06-14
Abstract
Abstract Disclosed is a magnetic head used for a vertical magnetizing system comprising a core having a pair of leg portions and an auxiliary magnetic pole which is arranged so as to face both leg portions. A closed magnetic path is formed by the core and the auxiliary magnetic pole. A sharp edge is formed at each end of the leg portions. A magnetic recording medium passes through the gap between the sharp edges and the auxiliary magnetic pole. When the magnetic recording medium passes through the gap, a high density magnetic recording operation is performed by the magnetic field produced by each sharp edge. Moreover, the recording operation can be effectively carried out due to the closed magnetic path and the recording magnetic field magnetized on the magnetic recording medium can be read out by using the same magnetic head as the magnetic head which is used for the recording operation. In an embodiment of a magnetic head of the invention, a magnetic thin film is coated on each surface of the side walls of the leg portions.
Inventors
- 👤 Shiro Nakagawa
- 👤 Toshiki Aoi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 19:57
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/1278
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
191 words
A magnetic head for exchanging a signal between said magnetic head and a magnetic recording medium during relative motion between said magnetic head and said magnetic recording medium, comprising: a first magnetic member having a pair of magnetic leg portions and a connecting portion magnetically connected between said magnetic leg portions, each of said magnetic leg portions including an end portion facing said magnetic recording medium said end portion having only one sharp edge line, substantially perpendicular to the direction of said relative motion; a coil wound on said first magnetic member; and a second magnetic member for forming a closed magnetic path together with said first magnetic member, said second magnetic member facing both of said end portions of said first magnetic member in such a manner that said magnetic recording medium is positioned between said first magnetic member and said second magnetic member, wherein the direction of the magnetic recording field applied to the magnetic recording medium is perpendicular to the surface of the magnetic recording medium such that the magnetic flux passes transversely through the magnetic recording medium whereby the magnetic recording is in the vertical magnetization mode.
Claim 2
Dependent Claim
191 words
A magnetic head for exchanging a signal between said magnetic head and a magnetic recording medium during relative motion between said magnetic head and said magnetic recording medium, comprising: a first magnetic member having a pair of magnetic leg portions and a connecting portion magnetically connected between said magnetic leg portions, each of said magnetic leg portions including an end portion facing said magnetic recording medium said end portion having only one sharp edge line, substantially perpendicular to the direction of said relative motion; a coil wound on said first magnetic member; and a second magnetic member for forming a closed magnetic path together with said first magnetic member, said second magnetic member facing both of said end portions of said first magnetic member in such a manner that said magnetic recording medium is positioned between said first magnetic member and said second magnetic member, wherein the direction of the magnetic recording field applied to the magnetic recording medium is perpendicular to the surface of the magnetic recording medium such that the magnetic flux passes transversely through the magnetic recording medium whereby the magnetic recording is in the vertical magnetization mode.
Claim 3
Dependent Claim
24 words
A magnetic head as recited in claim 1, wherein said second magnetic member is a magnetic layer which is provided on said recording medium.
Claim 4
Dependent Claim
25 words
A magnetic head as recited in claim 1, wherein non-magnetic material is inserted between said end portions of said magnetic leg portions as a spacer.
Claim 5
Dependent Claim
47 words
A magnetic head as recited in claim 1, wherein one side wall forming said sharp edge line is formed as a curved surface and the other side wall forming said sharp edge line is formed as a surface perpendicular to the surface of said magnetic recording medium.
Claim 6
Dependent Claim
34 words
A magnetic head as recited in claim 4, wherein a non-magnetic material is coated on the other side wall of said sharp edge line, whereby the other side wall is mechanically protected from wear.
Claim 7
Dependent Claim
17 words
A magnetic head as recited in claim 5, wherein said non-magnetic material is a non-magnetic metal conductor.
Claim 8
Dependent Claim
26 words
A magnetic head as recited in claim 1, wherein each of said end portions which face said magnetic recording medium is formed as a flat surface.
Claim 9
Dependent Claim
31 words
A magnetic head as recited in claim 7, wherein the shape of said flat surface is a trapezoid and one of the non-parallel edges of said trapezoid is said sharp edge.
Claim 10
Dependent Claim
48 words
A magnetic head as recited in claim 7, wherein each said flat surface is formed in such a way that the distance between said leg portions is minimum at the portion of the sharp edge line and gradually increases from the sharp edge line along the flat surfaces.
Claim 11
Dependent Claim
21 words
A magnetic head as recited in claim 7, wherein a non-magnetic material with high conductivity is inserted between said leg portions.
Claim 12
Dependent Claim
31 words
A magnetic head as recited in claims 3, 4, or 7, wherein a magnetic thin film is coated on at least one surface of a rear wall of said leg portions.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-09-09 | 1984-03-10 | 1984-09-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-09 | 1988-03-10 | 1988-09-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-09 | 1992-03-10 | 1992-09-09 | $7700.00 | Window Closed / Lapsed |