Patent US4427738A successfully refreshed from Google Patents.
US4427738A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1981-06-17
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Granted: 1984-01-24
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Expires: 2001-06-17
Abstract
Abstract A magnetic recording medium having a magnetic recording layer on one side of a non-magnetic base and a lubricant layer on the other side and which is used at a high tape speed of 2 to 10 m/sec. is disclosed. The lubricant layer is characterized by having a thickness of 2.5 to 5 μm and a surface roughness (Ra) of 0.33 to 0.72 μm.
Inventors
- 👤 Masaaki Fujiyama
- 👤 Nobutaka Yamaguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:45
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; G11B5/7356; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
110 words
A magnetic recording medium which is used at a high tape speed of 2 to 10 m/sec, comprising a non-magnetic base, a magnetic recording layer on a first side of said base and a lubricant layer on a second side of said base, wherein said magnetic recording layer comprises magnetic particles dispersed in a binder, and wherein said lubricant layer has a thickness of 2.5 to 5 μm and a surface roughness (Ra) of 0.33 to 0.72 μm, and comprises a lubricant provided in a binder, wherein the binder is a synthetic resin binder in an amount of 30 to 300 parts by weight based on 300 parts of lubricant.
Claim 2
Dependent Claim
110 words
A magnetic recording medium which is used at a high tape speed of 2 to 10 m/sec, comprising a non-magnetic base, a magnetic recording layer on a first side of said base and a lubricant layer on a second side of said base, wherein said magnetic recording layer comprises magnetic particles dispersed in a binder, and wherein said lubricant layer has a thickness of 2.5 to 5 μm and a surface roughness (Ra) of 0.33 to 0.72 μm, and comprises a lubricant provided in a binder, wherein the binder is a synthetic resin binder in an amount of 30 to 300 parts by weight based on 300 parts of lubricant.
Claim 3
Dependent Claim
17 words
A magnetic recording medium as claimed in claim 1 wherein said lubricant layer is comprised of graphite.
Claim 4
Dependent Claim
21 words
A magnetic recording medium as claimed in claim 1 wherein said lubricant layer is comprised of molybdenum disulfide and talc powder.
Claim 5
Dependent Claim
26 words
A magnetic recording medium as claimed in claim 2 wherein said graphite is comprised of particles having an average diameter of from 3 to 10 μm.
Claim 6
Dependent Claim
38 words
A magnetic recording medium as claimed in claim 1 wherein said lubricant layer is comprised of a dialkyl ketone having the structural formula ##STR4## wherein R and R' are independently aliphatic alkyls having 7 to 17 carbon atoms.
Claim 7
Dependent Claim
15 words
A magnetic recording medium as claimed in claim 5 wherein said dialkyl ketone is ##STR5##
Claim 8
Dependent Claim
30 words
A magnetic recording medium as claimed in claim 5 wherein said dialkyl ketone is contained in an amount of at least 0.5% by weight based on the weight of lubricant.
Claim 9
Dependent Claim
50 words
A magnetic recording medium as claimed in claim 5 or 6 wherein said dialkyl ketone is diheptadecyl ketone which is contained within said lubricant layer in combination with graphite, with said ketone being contained in an amount of at least 0.5% by weight based on the weight on said graphite.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-23 | 1987-07-25 | 1988-01-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-23 | 1991-07-25 | 1992-01-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-23 | 1995-07-25 | 1996-01-24 | $7700.00 | Window Closed / Lapsed |