US4734326A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1985-01-24
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Granted: 1988-03-29
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Expires: 2005-01-24
Abstract
Abstract A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, characterized in that the back coating layer is a coating layer comprising zinc sulfide and a resin binder.
Inventors
- 👤 Masaharu Nishimatsu
- 👤 Hiroyuki Arioka
- 👤 Toshiaki Ide
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 05:57
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70605; G11B5/714; G11B5/73; G11B5/735; G11B5/7356; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
71 words
A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the entire length of the other side of the substrate, characterized in that the back coating layer is a coating layer comprising a particulate zinc compound consisting essentially of zinc sulfide having an average particle size of at most 0.2 μm and a resin binder.
Claim 2
Dependent Claim
71 words
A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the entire length of the other side of the substrate, characterized in that the back coating layer is a coating layer comprising a particulate zinc compound consisting essentially of zinc sulfide having an average particle size of at most 0.2 μm and a resin binder.
Claim 3
Dependent Claim
63 words
The magnetic recording medium according to claim 1, wherein the magnetic recording layer is composed essentially of a ferromagnetic alloy powder dispersed in a resin binder and having a specific surface area of at least 48 m 2 /g as measured by BET method, and has a coercive force of at least 1000 Oe and a surface roughness of at most 0.08 μm.
Claim 4
Dependent Claim
18 words
The magnetic recording medium according to claim 1, wherein the magnetic recording layer is a thin ferromagnetic film.
References Cited (Backward Citations)
US4135032A
Cited
US4135031A
Cited
US4146031A
Cited
US4411963A
Cited
US4328935A
Cited
US4612244A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-29 | 1991-09-28 | 1992-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-29 | 1995-09-28 | 1996-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-29 | 1999-09-28 | 2000-03-29 | $7700.00 | Window Closed / Lapsed |