Patent US4442171A successfully refreshed from Google Patents.
US4442171A
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1982-03-09
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Granted: 1984-04-10
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Expires: 2002-03-09
Abstract
Abstract A magnetic recording medium comprising a nonmagnetic flexible substrate, a magnetic layer provided on the surface of the substrate and containing ferromagnetic grains dispersed in a binder, and a back layer provided on the back surface of the substrate. The magnetic recording medium has a stiffness (S TD ) of 6.0 or less. The friction coefficient (μ B ) of the back layer surface with respect to the axial direction of a loading post in a video tape recorder is controlled to satisfy the condition: 0≦μ.sub.B ≦0.1S.sub.TD -0.05 so as to make the magnetic recording medium highly resistant to damage due to movement in a video tape recorder.
Inventors
- 👤 Masami Sato
- 👤 Goro Akashi
- 👤 Yasutoshi Okuzawa
- 👤 Toshimitu Okutu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:25
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; G11B5/7356; G11B5/7358; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24479; Y10T428/24521; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
107 words
A magnetic recording medium comprising a non-magnetic flexible substrate, a magnetic layer provided on the surface of said substrate and containing ferromagnetic grains dispersed in a binder, and a back layer provided on the back surface of said substrate, wherein the stiffness (S TD ) of said magnetic recording medium is 6.0 or less, the surface roughness of said back layer is substantially 0.038 microns or less, the magnetic recording medium has a thickness of substantially 15.5 microns or less, and the friction coefficient (μ B ) of said back layer with respect to the axial direction of a loading post satisfies the condition: 0≦μ.sub.B ≦0.1S.sub.TD -0.05.
Claim 2
Dependent Claim
107 words
A magnetic recording medium comprising a non-magnetic flexible substrate, a magnetic layer provided on the surface of said substrate and containing ferromagnetic grains dispersed in a binder, and a back layer provided on the back surface of said substrate, wherein the stiffness (S TD ) of said magnetic recording medium is 6.0 or less, the surface roughness of said back layer is substantially 0.038 microns or less, the magnetic recording medium has a thickness of substantially 15.5 microns or less, and the friction coefficient (μ B ) of said back layer with respect to the axial direction of a loading post satisfies the condition: 0≦μ.sub.B ≦0.1S.sub.TD -0.05.
Claim 3
Dependent Claim
20 words
A magnetic recording medium as defined in claim 1 wherein said friction coefficient (μ B ) is 0.30 or less.
Claim 4
Dependent Claim
30 words
A magnetic recording medium as defined in claim 1 wherein said ferromagnetic grains are selected from the group consisting of ferromagnetic iron oxide, ferromagnetic chromium dioxide, and ferromagnetic alloy grains.
Claim 5
Dependent Claim
37 words
A magnetic recording medium as defined in claim 1 wherein said binder is selected from the group consisting of a thermoplastic resin, a thermosetting or reactive resin, and a mixture of two or more of these resins.
Claim 6
Dependent Claim
36 words
A magnetic recording medium as defined in claim 1 wherein said binder is contained in a proportion within the range of 8 to 150 parts by weight per 100 parts by weight of said ferromagnetic grains.
Claim 7
Dependent Claim
29 words
A magnetic recording medium as defined in claim 1 wherein said back layer is formed from a composition containing nitrocellulose, a polyurethane resin, a polyisocyanate, and CaCO 3 .
References Cited (Backward Citations)
US3515569A
Cited
US4135032A
Cited
US4071654A
Cited
US4175145A
Cited
US4153920A
Cited
US4318957A
Cited
US4328935A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-04-10 | 1987-10-10 | 1988-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-10 | 1991-10-10 | 1992-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-10 | 1995-10-10 | 1996-04-10 | $7700.00 | Window Closed / Lapsed |