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Patent US4153920A successfully refreshed from Google Patents.
US4153920A
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Recording method employing a magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1977-11-21
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Granted: 1979-05-08
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Expires: 1997-11-21
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
2026-10-23 19:50
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/657; G11B5/73; G11B5/739; G11B5/73923; G11B5/73927; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
83 words
In a method of recording or reproducing employing a magnetic recording medium wherein the relative speed between the magnetic recording head and the magnetic recording medium is v μm/sec, the improvement comprising employing as the magnetic recording medium, a non-binder type magnetic recording medium comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, the support having a surface roughness of 0.04 to 0.08 μm and a period of surface roughness of at most v/10 6 μm.
Claim 2
Dependent Claim
83 words
In a method of recording or reproducing employing a magnetic recording medium wherein the relative speed between the magnetic recording head and the magnetic recording medium is v μm/sec, the improvement comprising employing as the magnetic recording medium, a non-binder type magnetic recording medium comprising a ferromagnetic metal thin film as a magnetic recording layer on a non-magnetic flexible support, the support having a surface roughness of 0.04 to 0.08 μm and a period of surface roughness of at most v/10 6 μm.
Claim 3
Dependent Claim
29 words
The method 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
46 words
The method 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
20 words
The method as claimed in claim 1, wherein the ferromagnetic metal thin film is formed by vapor deposition or plating.
Claim 6
Dependent Claim
62 words
The method as claimed in claim 1, wherein the non-magnetic flexible support is a material selected from the group consisting of cellulose acetate, nitrocellulose, 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, polyvinylidene chloride, polycarbonates, polyimides and polyesters such as polyethylene terephthalate and polybutylene terephthalate.
Claim 7
Dependent Claim
20 words
The method as claimed in claim 1, wherein the non-magnetic flexible support has a thickness of 4 to 50 μm.
Claim 8
Dependent Claim
18 words
The method as claimed in claim 1, wherein the magnetic recording medium is a tape, sheet or card.
Claim 9
Dependent Claim
21 words
The method as claimed in claim 1, wherein the ferromagnetic metal thin film has a thickness of 0.05 to 2 μm.
Claim 10
Dependent Claim
98 words
In a method of recording or reproducing employing a magnetic recording medium wherein the relative speed between the magnetic recording head and the magnetic recording medium is v μm/sec, the improvement comprising employing as the magnetic recording medium a non-binder type magnetic recording medium comprisng 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 undercoat layer having a surface roughness of 0.06 to 0.07 μm and a period of surface roughness of at most v/10 6 μm.
Claim 11
Dependent Claim
98 words
In a method of recording or reproducing employing a magnetic recording medium wherein the relative speed between the magnetic recording head and the magnetic recording medium is v μm/sec, the improvement comprising employing as the magnetic recording medium a non-binder type magnetic recording medium comprisng 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 undercoat layer having a surface roughness of 0.06 to 0.07 μm and a period of surface roughness of at most v/10 6 μm.
Claim 12
Dependent Claim
37 words
The method as claimed in claim 9, wherein the undercoat layer is 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 13
Dependent Claim
20 words
The method as claimed in claim 10, wherein the undercoated layer has a thickness of not more than 10 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) | 1982-05-07 | 1982-11-06 | 1983-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-07 | 1986-11-06 | 1987-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-07 | 1990-11-06 | 1991-05-08 | $7700.00 | Window Closed / Lapsed |