Patent US4677024A successfully refreshed from Google Patents.
US4677024A
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Magnetic recording medium
Assignee: Maxell Ltd
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Filing: 1984-11-16
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Granted: 1987-06-30
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Expires: 2004-11-16
Abstract
Abstract Magnetic recording medium comprising a magnetic layer formed by magnetic powder including acicular magnetic powder with the magnetic anisotropy to be oriented perpendicular to the acicular direction which is oriented in parallel with the magnetic layer.
Inventors
- 👤 Shinichi Kitahata
- 👤 Mikio Kishimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:12
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/852; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70642; G11B5/70678; G11B5/714; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
57 words
A magnetic recording medium which comprises a substrate having a magnetic layer coated thereon, said magnetic layer comprising a needle-shaped magnetic powder in a binder with the magnetic anisotropy of said powder being in a direction perpendicular to the longitudinal axis of the needle-shaped powder, said longitudinal axis being in the plane parallel to the magnetic layer.
Claim 2
Dependent Claim
57 words
A magnetic recording medium which comprises a substrate having a magnetic layer coated thereon, said magnetic layer comprising a needle-shaped magnetic powder in a binder with the magnetic anisotropy of said powder being in a direction perpendicular to the longitudinal axis of the needle-shaped powder, said longitudinal axis being in the plane parallel to the magnetic layer.
Claim 3
Dependent Claim
30 words
The magnetic recording medium according to claim 1, wherein the grain diameter of the needle-shaped magnetic powder is less than 0.5 micrometer with the axis ratio being greater than 5.
References Cited (Backward Citations)
US3694261A
Cited
US4451535A
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US4442159A
Cited
US4465735A
Cited
US4457982A
Cited
US4511617A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-29 | 1990-12-29 | 1991-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-29 | 1994-12-29 | 1995-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-29 | 1998-12-29 | 1999-06-30 | $7700.00 | Window Closed / Lapsed |