US4396668A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
•
Filing: 1981-03-23
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Granted: 1983-08-02
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Expires: 2001-03-23
Abstract
Abstract A magnetic recording medium obtained by coating a magnetic metallic powder with a binder on a non-magnetic substrate, wherein said magnetic metallic powder is mainly made of acicular particles obtained by a dry reduction process and said magnetic recording medium has a residual magnetic flux density of greater than 2,600 gauss, a coercive force of 1,300 to 1,800 Oe, a thickness of a magnetic layer of 1.5 to 3.5 μm and a C/N ratio (carrier signal/noise level) in video band of greater than 4 dB of the C/N ratio of the standard video tape.
Inventors
- 👤 Seitoku Saito
- 👤 Hideo Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:32
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; H; H01; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/06; H01F1/065; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
110 words
A magnetic recording tape of a width of 1/4 inch having a residual magnetic flux density of greater than 2,600 gauss, a coercive force of 1,300 to 1,800 Oe, a thickness of a magnetic layer of 1.5 to 3.5 μm and a C/N ratio (carrier signal/noise level) in video band of greater than 4 dB of the C/N ratio of the standard video tape, said tape comprising a non-magnetic substrate coated with a composition comprising a magnetic metallic powder and a binder, the magnetic metallic powder comprising mainly acicular particles obtained by the dry reduction of an acicular iron oxide or oxyhydroxide in a hydrogen gas atmosphere at high temperature.
Claim 2
Dependent Claim
110 words
A magnetic recording tape of a width of 1/4 inch having a residual magnetic flux density of greater than 2,600 gauss, a coercive force of 1,300 to 1,800 Oe, a thickness of a magnetic layer of 1.5 to 3.5 μm and a C/N ratio (carrier signal/noise level) in video band of greater than 4 dB of the C/N ratio of the standard video tape, said tape comprising a non-magnetic substrate coated with a composition comprising a magnetic metallic powder and a binder, the magnetic metallic powder comprising mainly acicular particles obtained by the dry reduction of an acicular iron oxide or oxyhydroxide in a hydrogen gas atmosphere at high temperature.
Claim 3
Dependent Claim
25 words
The magnetic recording tape according to claim 1 wherein said acicular particles of the magnetic metallic powder are surface treated to prevent a surface oxidation.
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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) | 1986-08-01 | 1987-01-31 | 1987-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-01 | 1991-01-31 | 1991-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-01 | 1995-01-31 | 1995-08-02 | $7700.00 | Window Closed / Lapsed |