US4840843A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1987-10-19
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Granted: 1989-06-20
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Expires: 2007-10-19
Abstract
Abstract A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a thin magnetic metal film and a protective layer mainly comprising carbon having a graphite structure containing at least one element selected from the group consisting of Mn, Mo, Nb, Ta, Ti, V, Cr and W.
Inventors
- 👤 Kunihiko Sano
- 👤 Makoto Nagao
- 👤 Akira Nahara
- 👤 Yasuo Nishikawa
- 👤 Hiroyuki Iwasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:14
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/725; G11B5/726; G11B5/7262; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/30
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
79 words
A magnetic recording medium comprising a non-magnetic support having provided thereon a thin magnetic metal film and a protective layer mainly comprising carbon having a graphite structure containing at least one element selected from the group consisting of Mn, Mo, Nb, Ta, Ti, V, Cr and W, wherein said at least one element is present in an amount of from 0.5 to 10 wt. % and wherein the thickness of said protective layer is from 10 to 1,000 Å.
Claim 2
Dependent Claim
79 words
A magnetic recording medium comprising a non-magnetic support having provided thereon a thin magnetic metal film and a protective layer mainly comprising carbon having a graphite structure containing at least one element selected from the group consisting of Mn, Mo, Nb, Ta, Ti, V, Cr and W, wherein said at least one element is present in an amount of from 0.5 to 10 wt. % and wherein the thickness of said protective layer is from 10 to 1,000 Å.
Claim 3
Dependent Claim
34 words
A magnetic recording medium as in claim 1, wherein a lubricating layer mainly comprising organic compounds having a mercapto group, phosphate compounds, or fluorine type lubricating agents is additionally provided on said protective layer.
Claim 4
Dependent Claim
41 words
A magnetic recording medium as in claim 1, wherein said protective layer contains at least one element selected from the group consisting of Mn, Mo, Nb, Ta, Ti, V, Cr and W in an amount of 10 wt % or less.
Claim 5
Dependent Claim
42 words
A magnetic recording medium as in claim 1, wherein said protective layer contains at least one element selected from the group consisting of Mn, Mo, Nb, Ta, Ti, V, Cr and W in an amount of from 0.5 to 5 wt %.
Claim 6
Dependent Claim
21 words
A magnetic recording medium as in claim 1, wherein the thickness of said protective layer is from 50 to 200 Å.
Claim 7
Dependent Claim
34 words
A magnetic recording medium as in claim 2, wherein said lubricating layer mainly comprises an organic compound having a mercapto group, selected from an alkylmercaptan and a heterocyclic compound substituted with a mercapto group.
Claim 8
Dependent Claim
28 words
A magnetic recording medium as in claim 2, wherein said lubricating layer mainly comprises an organic compound having a mercapto group and an ester bond in a molecule.
Claim 9
Dependent Claim
25 words
A magnetic recording medium as in claim 2, wherein said lubricating layer mainly comprises phosphate compounds having alkyl group having 10 or more carbon atoms.
Claim 10
Dependent Claim
25 words
A magnetic recording medium as in claim 2, wherein said lubricating layer mainly comprises phosphate compound having aliphatic group having 12 or more carbon atoms.
Claim 11
Dependent Claim
42 words
A magnetic recording medium as in claim 2, wherein said lubricating layer mainly comprises fluorine type lubricating agent selected from compounds having a perfluoroalkyl group or perfluoroalkenyl group, perfluoroalkylene oxide polymers and derivatives thereof, and a polymer or copolymer of fluorine-substituted ethylene.
Claim 12
Dependent Claim
23 words
A magnetic recording medium as in claim 2, wherein the thickness of said lubricating layer is from 0.5 to 100 mg/m 2 .
Claim 13
Dependent Claim
23 words
A magnetic recording medium as in claim 2, wherein the thickness of said lubricating layer is from 2 to 20 mg/m 2 .
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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) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |