US4423452A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1981-07-08
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Granted: 1983-12-27
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Expires: 2001-07-08
Abstract
Abstract A magnetic recording medium comprises a substrate coated with a magnetic layer comprising a magnetic powder and a fine titanium oxide powder having a particle diameter of at least 0.4μ and at least one other fine hard non-magnetic powder.
Inventors
- 👤 Norifumi Kajimoto
- 👤 Yoshio Kawakami
- 👤 Kinji Sasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:07
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/7085
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
40 words
A magnetic recording medium which comprises a substrate coated with a magnetic layer comprising a magnetic powder and a fine titanium oxide powder having a particle diameter of at least 0.4μ and at least one other fine hard non-magnetic powder.
Claim 2
Dependent Claim
40 words
A magnetic recording medium which comprises a substrate coated with a magnetic layer comprising a magnetic powder and a fine titanium oxide powder having a particle diameter of at least 0.4μ and at least one other fine hard non-magnetic powder.
Claim 3
Dependent Claim
31 words
The magnetic recording medium according to claim 1 wherein the content of said fine titanium oxide powder is in a range of up to 20 wt.% based on said magnetic powder.
Claim 4
Dependent Claim
35 words
The magnetic recording medium according to claim 1 wherein said other fine hard non-magnetic powder is at least one of alumina, chromium oxide, silicon oxide, cerium oxide, beryllium oxide, boron carbide, silicon carbide and zirconium.
Claim 5
Dependent Claim
22 words
The magnetic recording medium according to claim 1 wherein said fine titanium oxide powder has a particle diameter of 0.4 to 2μ.
Claim 6
Dependent Claim
31 words
The magnetic recording medium according to claim 1 wherein the total content of said hard non-magnetic powders is in a range of 0.5 to 20 wt.% based on said magnetic 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) | 1986-12-26 | 1987-06-27 | 1987-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-26 | 1991-06-27 | 1991-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-26 | 1995-06-27 | 1995-12-27 | $7700.00 | Window Closed / Lapsed |