Patent US4450199A successfully refreshed from Google Patents.
US4450199A
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1981-04-07
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Granted: 1984-05-22
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Expires: 2001-04-07
Abstract
Abstract A magnetic recording medium is disclosed which comprises a nonmagnetic support and a magnetic layer formed thereon, said magnetic layer having a center-line average surface roughness of not more than 2.1×10 -2 μ and at least one property selected from an average pore size of at least 500 Å and a porosity of at least 30%.
Inventors
- 👤 Eiichi Tadokoro
- 👤 Masaaki Fujiyama
- 👤 Goro Akashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:13
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249986; Y10T428/31504; Y10T428/31551; Y10T428/31565; Y10T428/31855; Y10T428/3188; Y10T428/31884; Y10T428/31935
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
68 words
A magnetic recording medium comprising a nonmagnetic support and a magnetic layer formed thereon, said magnetic layer comprising a magnetic powder and a binder which comprises a thermosetting resin, said magnetic layer having a center-line average surface roughness of not more than 2.1×10 -2 μ, and at least one property selected from an average particle size of at least 500 Å and a porosity of at least 30%.
Claim 2
Dependent Claim
68 words
A magnetic recording medium comprising a nonmagnetic support and a magnetic layer formed thereon, said magnetic layer comprising a magnetic powder and a binder which comprises a thermosetting resin, said magnetic layer having a center-line average surface roughness of not more than 2.1×10 -2 μ, and at least one property selected from an average particle size of at least 500 Å and a porosity of at least 30%.
Claim 3
Dependent Claim
41 words
A magnetic recording medium as in claim 1 wherein the magnetic layer has a center-line average surface roughness of not more than 2.1×10 -2 μ, an average pore size of at least 500 Å, and a porosity of at least 30%.
Claim 4
Dependent Claim
24 words
A magnetic recording medium as in claim 1 or 2 wherein the center line average surface roughness is not more than 1.9×10 -2 microns.
Claim 5
Dependent Claim
20 words
A magnetic recording medium as in claim 1 or 2 wherein the average pore size of at least 610 Å.
Claim 6
Dependent Claim
17 words
A magnetic recording medium as in claim 1 or 2 wherein the porosity is at least 34%.
Claim 7
Dependent Claim
16 words
A magnetic recording medium as in claim 1 wherein the binder contains nitrocellulose or vinyl chloride.
Claim 8
Dependent Claim
19 words
A magnetic recording medium as in claim 1 wherein the thermosetting resin is a binder having an isocyanate group.
Claim 9
Dependent Claim
11 words
A magnetic recording medium as in claim 1, which is calendered.
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) | 1987-05-22 | 1987-11-21 | 1988-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-22 | 1991-11-21 | 1992-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-22 | 1995-11-21 | 1996-05-22 | $7700.00 | Window Closed / Lapsed |