US4681669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing magnetic recording media
Assignee: Nippon Gakki Co Ltd
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Filing: 1985-11-14
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Granted: 1987-07-21
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Expires: 2005-11-14
Abstract
Abstract In production of magnetic recording media by anode oxidation of an Al predominant substrate, deposition of ferromagnetic substance in substrate pores and final grinding, use of a substrate having a surface K-value of 0.5 or larger enables easy production of media with surface roughness well suited for ideal high density magnetic recording. The K-value is the ratio of X-ray reflection intensity of the crystal plane S(1,1,1) and the toal X-ray reflection intensity of all crystal planes.
Inventors
- 👤 Toshiro Takahashi
- 👤 Tadao Tokushima
- 👤 Yoshifumi Suzuki
- 👤 Yukio Wakui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:01
CPC Classifications
C; C25; C25D; C25D11/00; C25D11/02; C25D11/04; C25D11/18; C25D11/20; G; G11; G11B; G11B5/00; G11B5/84; Y; Y10; Y10S; Y10S205/00; Y10S205/922
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
99 words
Improved method for producing magnetic recording media comprising the steps of subjecting an Al predominant substrate to anode oxidation to form thereon an Al surface layer with pores, depositing ferromagnetic substance in said pores of said Al surface layer, and grinding said Al surface layer, the surface of said Al predominant substrate having a K-value specified by ##EQU1## in which S (1 1 1) is the X-ray reflection intensity by the (1 1 1) crystal plane of Al and ΣS (h k l) is the total X-ray reflection intensity by all crystal planes of Al, both by Miller indices.
Claim 2
Dependent Claim
99 words
Improved method for producing magnetic recording media comprising the steps of subjecting an Al predominant substrate to anode oxidation to form thereon an Al surface layer with pores, depositing ferromagnetic substance in said pores of said Al surface layer, and grinding said Al surface layer, the surface of said Al predominant substrate having a K-value specified by ##EQU1## in which S (1 1 1) is the X-ray reflection intensity by the (1 1 1) crystal plane of Al and ΣS (h k l) is the total X-ray reflection intensity by all crystal planes of Al, both by Miller indices.
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) | 1990-07-20 | 1991-01-19 | 1991-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-20 | 1995-01-19 | 1995-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-20 | 1999-01-19 | 1999-07-21 | $7700.00 | Window Closed / Lapsed |