USRE28866E
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording coating
Assignee: International Business Machines Corp
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Filing: 1975-10-08
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Granted: 1976-06-15
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Expires: 1995-10-08
Abstract
Abstract A magnetic recording medium, such as a magnetic recording disk, having a magnetic recording layer that contains ferromagnetic and nonferromagnetic particles dispersed in a binder. The nonferromagnetic particles are disposed in the binder to be substantially equal to the thickness of the coated layer, and are of a material having a greater hardness than that of the binder.
Inventors
- 👤 Joseph E. Haefele
- 👤 Cecil R. Hawkins
- 👤 Ronald E. Kubec
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:53
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/7085; Y; Y10; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
72 words
A magnetic recording medium compising ferromagnetic and alumina particles dispersed in a binder as a unitary coating upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying non-magnetic substrate and present in an amount not above 5% by weight of the ferromagnetic and alumina particles.
Claim 2
Dependent Claim
72 words
A magnetic recording medium compising ferromagnetic and alumina particles dispersed in a binder as a unitary coating upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying non-magnetic substrate and present in an amount not above 5% by weight of the ferromagnetic and alumina particles.
Claim 3
Dependent Claim
73 words
A magnetic recording medium comprising ferromagnetic and alumina particles dispersed in a binder as a unitary coating upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying non-magnetic substrate and present in an amount between 3 to 5% by weight of the ferromagnetic and alumina particles.
Claim 4
Dependent Claim
73 words
A magnetic recording medium comprising ferromagnetic and alumina particles dispersed in a binder as a unitary coating upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying non-magnetic substrate and present in an amount between 3 to 5% by weight of the ferromagnetic and alumina particles.
Claim 5
Dependent Claim
76 words
A magnetic recording medium comprising ferromagnetic and alumina particles dispersed in a binder as a unitary coating of substantially 50 microinches upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying nonmagnetic substrate and present in an amount not above 5% by weight of the ferromagnetic and alumina particles.
Claim 6
Dependent Claim
76 words
A magnetic recording medium comprising ferromagnetic and alumina particles dispersed in a binder as a unitary coating of substantially 50 microinches upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying nonmagnetic substrate and present in an amount not above 5% by weight of the ferromagnetic and alumina particles.
Claim 7
Dependent Claim
77 words
A magnetic recording medium comprising ferromagnetic and alumina particles dispersed in a binder as a unitary coating of substantially 50 microinches upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying non-magnetic substrate and present in an amount between 3 to 5% by weight of the ferromagnetic and alumina particles.
Claim 8
Dependent Claim
77 words
A magnetic recording medium comprising ferromagnetic and alumina particles dispersed in a binder as a unitary coating of substantially 50 microinches upon a non-magnetic substrate, each of the alumina particles disposed in said binder to be substantially equal to the thickness of the medium to form a solid barrier between the surface of the medium and the underlying non-magnetic substrate and present in an amount between 3 to 5% by weight of the ferromagnetic and alumina particles.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-06-15 | 1979-12-15 | 1980-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-06-15 | 1983-12-15 | 1984-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-06-15 | 1987-12-15 | 1988-06-15 | $7700.00 | Window Closed / Lapsed |