US4455345A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1983-01-11
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Granted: 1984-06-19
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Expires: 2003-01-11
Abstract
Abstract A magnetic recording medium is disclosed. The medium is comprised of a support having a magnetic layer coated thereon. The magnetic layer is comprised of ferromagnetic metal powder and a binder. The ferromagnetic metal powder has a specific surface area of 35 to 70 m 2 /g, a saturation magnetization (σ s ) of 120 to 160 emu/g and a metal content of 75 to 98 wt %. The magnetic recording medium has a high S/N ratio, particularly a high video S/N ratio and has stable magnetic properties.
Inventors
- 👤 Hajime Miyatuka
- 👤 Akira Kasuga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:46
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70605; G11B5/70615; G11B5/708; G11B5/7085; G11B5/714; H; H04; H04H; H04H2201/00; H04H2201/10; H04H2201/13; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
56 words
A magnetic recording medium, comprising: a support having coated thereon; a magnetic layer containing a ferromagnetic powder and a binder, said ferromagnetic metal powder having a specific surface area of 35 to 70 m 2 /g, a saturation magnetization (σ s ) of 120 to 160 emu/g and a metal content of 75 to 98 wt%.
Claim 2
Dependent Claim
56 words
A magnetic recording medium, comprising: a support having coated thereon; a magnetic layer containing a ferromagnetic powder and a binder, said ferromagnetic metal powder having a specific surface area of 35 to 70 m 2 /g, a saturation magnetization (σ s ) of 120 to 160 emu/g and a metal content of 75 to 98 wt%.
Claim 3
Dependent Claim
28 words
A magnetic recording medium as claimed in claim 1, wherein the ferromagnetic powder has a specific surface area within the range of 40 to 65 m 2 /g.
Claim 4
Dependent Claim
29 words
A magnetic recording medium as claimed in claim 2, wherein the specific surface area of the ferromagnetic powder is within the range of 45 to 60 m 2 /g.
Claim 5
Dependent Claim
28 words
A magnetic recording medium as claimed in claim 1, wherein the ferromagnetic powder has a saturation magnetization (σ s ) within a range of 125 to 150 emu/g.
Claim 6
Dependent Claim
28 words
A magnetic recording medium as claimed in claim 4, wherein the ferromagnetic powder has a saturation magnetization (σ s ) within the range of 128 to 145 emu/g.
Claim 7
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 1, wherein the ferromagnetic powder has a metal content within the range of 78 to 95 wt%.
Claim 8
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 6, wherein the ferromagnetic powder has a metal content within the range of 80 to 93 wt%.
Claim 9
Dependent Claim
28 words
A magnetic recording medium as claimed in claim 1, wherein the volume ratio of the ferromagnetic powder to the binder is within the range of 2:1 to 1:2.
Claim 10
Dependent Claim
25 words
A magnetic recording medium as claimed in claim 1, wherein the ferromagnetic powder is an alloy of Fe containing 1 to 15 wt% of Ni.
Claim 11
Dependent Claim
67 words
A magnetic recording medium as claimed in claim 1, wherein the magnetic layer is further comprised of: a fatty acid ester present in an amount of 1 to 12 wt% based on the weight of the ferromagnetic powder; and an abrasive agent having a hardness of 6 Moh's or more present in an amount of 1 to 10 wt% based on the weight of the ferromagnetic powder.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-19 | 1987-12-19 | 1988-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-19 | 1991-12-19 | 1992-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-19 | 1995-12-19 | 1996-06-19 | $7700.00 | Window Closed / Lapsed |