Patent US3501278A successfully refreshed from Google Patents.
US4097650A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1976-08-24
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Granted: 1978-06-27
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Expires: 1996-08-24
Abstract
Abstract This invention relates to a magnetic recording medium comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, in which the surface roughness of the support is 0.10 μm or less and the period of the surface roughness is v/10 6 μm or less where v represents a relative speed between a magnetic head and magnetic recording medium by μm/sec. In the case of providing an undercoated layer between the magnetic recording layer and non-magnetic flexible support, the surface roughness of the undercoated layer is adjusted to 0.10 μm or less and the period of the surface roughness is adjusted to v/10 6 μm or less.
Inventors
- 👤 Ryuji Shirahata
- 👤 Tatsuji Kitamoto
- 👤 Masaaki Suzuki
- 👤 Shin-ichiro Dezawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:36
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/657; H; H01; H01F; H01F10/00; H01F10/26; H01F10/28; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/266; Y10T428/269; Y10T428/31
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
80 words
A non-binder type magnetic recording medium for use in recording at a relative speed, v, to a magnetic reproducing head, comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, in which the surface roughness of the support is between 0.04 and 0.08 μm and the period of the surface roughness is at most v/10 6 μm where v is the relative speed between the magnetic head and the magnetic recording medium in μm/sec.
Claim 2
Dependent Claim
80 words
A non-binder type magnetic recording medium for use in recording at a relative speed, v, to a magnetic reproducing head, comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, in which the surface roughness of the support is between 0.04 and 0.08 μm and the period of the surface roughness is at most v/10 6 μm where v is the relative speed between the magnetic head and the magnetic recording medium in μm/sec.
Claim 3
Dependent Claim
31 words
The magnetic recording medium as claimed in claim 1, wherein the ferromagnetic metal thin film is selected from the group consisting of iron, cobalt, nickel, other ferromagnetic metal and ferromagnetic alloy.
Claim 4
Dependent Claim
48 words
The magnetic recording medium as claimed in claim 2, wherein the ferromagnetic alloy is Fe-Co, Fe-Ni, Co-Ni, Fe-Si, Fe-Rh, Fe-V, Co-P, Co-B, Co-Si, Co-V, Co-Y, Co-La, Co-Ce, Co-Pr, Co-Sm, Co-Mn, Fe-Co-Ni, Co-Ni-P, Co-Ni-B, Co-Ni-Ag, Co-Ni-Nd, Co-Ni-Ce, Co-Ni-Zn, Co-Ni-Cu, Co-Ni-Hg, Co-Ni-W, Co-Ni-Re, Co-Mn-P, Co-Zn-P, Co-Pb-P, Co-Sm-Cu, Co-Ni-Zn-P or Co-Ni-Mn-P.
Claim 5
Dependent Claim
22 words
The magnetic recording medium as claimed in claim 1, wherein the ferromagnetic metal thin film is formed by vapor deposition or plating.
Claim 6
Dependent Claim
66 words
The magnetic recording medium as claimed in claim 1, wherein the non-magnetic flexible support is of a material selected from the group consisting of cellulose acetate, notrocellulose, ethyl cellulose, methyl cellulose, polyamides, polymethyl methacrylate, polytetrafluoroethylene, polytrifluoroethylene, polymers and copolymers of α-olefins such as ethylene and propylene, polymers and copolymers of vinyl chloride, poly vinylidene chloride, polycarbonates, polyimides and polyesters such as polyethylene terephthalate and polybutylene terephthalate.
Claim 7
Dependent Claim
22 words
The magnetic recording medium as claimed in claim 1, wherein the non-magnetic flexible support has a thickness of 4 to 50 μm.
Claim 8
Dependent Claim
16 words
The magnetic recording medium as claimed in claim 1, which is a tape, sheet or card.
Claim 9
Dependent Claim
93 words
A non-binder type magnetic recording medium for use in recording at a relative speed, v, to a magnetic reproducing head, comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, in which an undercoat layer is provided between the support and magnetic recording layer, the surface roughness of the undercoat layer is between 0.06 and 0.07 μm and the period of the surface roughness is at most v/10 6 μm where v is the relative speed between the magnetic head and the magnetic recording medium in μ/sec.
Claim 10
Dependent Claim
93 words
A non-binder type magnetic recording medium for use in recording at a relative speed, v, to a magnetic reproducing head, comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, in which an undercoat layer is provided between the support and magnetic recording layer, the surface roughness of the undercoat layer is between 0.06 and 0.07 μm and the period of the surface roughness is at most v/10 6 μm where v is the relative speed between the magnetic head and the magnetic recording medium in μ/sec.
Claim 11
Dependent Claim
40 words
The magnetic recording medium as claimed in claim 8, wherein the undercoated layer is of a material selected from the group consisting of acrylonitrile-butadiene-styrene copolymers, epoxy resins, vinyl chloride-vinyl acetate copolymers, nitrocellulose, polyvinyl alcohol, gelatin, nitrile rubbers and acrylic rubbers.
Claim 12
Dependent Claim
22 words
The magnetic recording medium as claimed in claim 8, wherein the undercoat layer has a thickness of not more than 10 μm.
Claim 13
Dependent Claim
23 words
The magnetic recording medium as claimed in claim 1, wherein the ferromagnetic metal thin film has a thickness of 0.05 to 2 μm.
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) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |