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US4702959A
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1986-03-19
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Granted: 1987-10-27
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Expires: 2006-03-19
Abstract
Abstract A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on one side of the substrate and a back coating layer formed on the other side of the substrate, characterized in that the magnetic recording layer contains a hexagonal system plate crystal magnetic powder having a particle size of at most 0.2 μm, and the back coating layer contains a binder composed of a radiation curable resin and has an electric resistance of at most 10 10 Ω/cm 2 .
Inventors
- 👤 Toru Shimozawa
- 👤 Masaharu Nishimatsu
- 👤 Yoshiaki Saito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:01
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
122 words
A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer formed on one side of said substrate and a back coating layer formed on the other side of said substrate, wherein said magnetic recording layer contains a hexagonal system plate crystal magnetic powder having a particle size of at most 0.2 micron, and wherein said back coating layer comprises a binder comprised of a radiation curable resin, wherein said back coating layer has an electrical resistance of at most 10 10 Ω/cm 2 , and wherein said back coating layer has E' of from 500-1500 kg/mm 2 and a surface roughness of at most 0.20 micron as measured at a cutoff of 0.17 mm by the 20 point average method.
Claim 2
Dependent Claim
122 words
A magnetic recording medium, comprising a non-magnetic substrate, a magnetic recording layer formed on one side of said substrate and a back coating layer formed on the other side of said substrate, wherein said magnetic recording layer contains a hexagonal system plate crystal magnetic powder having a particle size of at most 0.2 micron, and wherein said back coating layer comprises a binder comprised of a radiation curable resin, wherein said back coating layer has an electrical resistance of at most 10 10 Ω/cm 2 , and wherein said back coating layer has E' of from 500-1500 kg/mm 2 and a surface roughness of at most 0.20 micron as measured at a cutoff of 0.17 mm by the 20 point average method.
Claim 3
Dependent Claim
47 words
The magnetic recording medium according to claim 1, wherein the magnetic powder is a hexagonal system plate crystal barium ferrite magnetic powder having an aspect ratio of at least 6 and the magnetic recording layer has an electric resistance of more than 10 10 Ω/cm 2 .
Claim 4
Dependent Claim
40 words
The magnetic recording medium according to claim 1, wherein the magnetic recording layer is provided with a conductive undercoating layer so that the overall electric reisistance at the magnetic recording layer side is at most 10 10 Ω/cm 2 .
Claim 5
Dependent Claim
21 words
The magnetic recording medium according to claim 3, herein the hexagonal system plate crystal magnetic powder is a barium ferrite powder.
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) | 1990-10-26 | 1991-04-27 | 1991-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-26 | 1995-04-27 | 1995-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-26 | 1999-04-27 | 1999-10-27 | $7700.00 | Window Closed / Lapsed |