US4632866A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1985-03-26
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Granted: 1986-12-30
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Expires: 2005-03-26
Abstract
Abstract In a coating type magnetic recording medium, a base film is coated with a magnetic paint composition comprising a binder and a magnetic powder mixture of magnetic metal particles with magnetic metal carbide particles or magnetic metal particles having a metal carbide coating on the surface thereof. Preferably, the metal is iron and the metal carbide is iron carbide.
Inventors
- 👤 Yuichi Kubota
- 👤 Akio Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:01
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70605; G11B5/70615; G11B5/70626; G11B5/708; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2998; Y10T428/30
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
70 words
In a magnetic recording medium comprising a substrate coated with a magnetic paint composition having magnetic powder dispersed in a binder, the improvement wherein the magnetic powder is a mixture of (a) magnetic metal particles and (b) magnetic iron carbide particles and/or magnetic metal particles having an iron carbide coating on the surface thereof, with the weight ratio of (a) to (b) being in the range between 97:3 and 20:80.
Claim 2
Dependent Claim
70 words
In a magnetic recording medium comprising a substrate coated with a magnetic paint composition having magnetic powder dispersed in a binder, the improvement wherein the magnetic powder is a mixture of (a) magnetic metal particles and (b) magnetic iron carbide particles and/or magnetic metal particles having an iron carbide coating on the surface thereof, with the weight ratio of (a) to (b) being in the range between 97:3 and 20:80.
Claim 3
Dependent Claim
26 words
The magnetic recording medium of claim 1 wherein the iron carbide has the formula Fe n C wherein n is a number of at least 2.
Claim 4
Dependent Claim
18 words
The magnetic recording medium of claim 1 or 2 wherein all the magnetic particles are of needle shape.
Claim 5
Dependent Claim
25 words
The magnetic recording medium of claim 1 wherein the magnetic powder is a mixture of (a) magnetic metal particles and (b) magnetic iron carbide particles.
Claim 6
Dependent Claim
29 words
The magnetic recording medium of claim 1 wherein the magnetic powder is a mixture of (a) magnetic metal particles and (b) magnetic metal particles having an irom carbide coating.
References Cited (Backward Citations)
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Cited
US3572993A
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US4137361A
Cited
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Cited
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Cited
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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) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |