Patent US4798761A successfully refreshed from Google Patents.
US4670337A
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Magnetic recording medium
Assignee: TDK Corp
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Filing: 1985-07-29
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Granted: 1987-06-02
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Expires: 2005-07-29
Abstract
Abstract In a magnetic recording medium comprising a base and a magnetic coating layer formed thereon which consists of ferromagnetic particles dispersed in a binder, the magnetic layer contains from 3 to 15 percent by weight, on the basis of the magnetic powder weight, of abrasive particles having a Mohs hardness of 6 or upward, in such a manner that the average number of the abrasive particles per unit area of the magnetic layer surface is at least 0.25 per square micron. The magnetic powder is a magnetic metal powder based on iron, and the abrasive particles are angular rather than granular in shape.
Inventors
- 👤 Yasumichi Tokuoka
- 👤 Hitoshi Arai
- 👤 Norio Higuchi
- 👤 Hideki Hotsuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:04
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/7085; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
80 words
A magnetic recording medium comprising a base and a magnetic coating layer formed thereon which consists of ferromagnetic particles dispersed in a binder, said magnetic layer containing from 3 to 15 percent by weight, on the basis of the magnetic powder weight, of abrasive particles having a Mohs hardness of 6 or upward, in such a manner that the average number of the abrasive particles per unit area of the magnetic layer surface is at least 0.25 per square micron.
Claim 2
Dependent Claim
80 words
A magnetic recording medium comprising a base and a magnetic coating layer formed thereon which consists of ferromagnetic particles dispersed in a binder, said magnetic layer containing from 3 to 15 percent by weight, on the basis of the magnetic powder weight, of abrasive particles having a Mohs hardness of 6 or upward, in such a manner that the average number of the abrasive particles per unit area of the magnetic layer surface is at least 0.25 per square micron.
Claim 3
Dependent Claim
20 words
A magnetic recording medium according to claim 1 wherein the magnetic powder is a magnetic metal powder based on iron.
Claim 4
Dependent Claim
16 words
A magnetic recording medium according to claim 1 or 2 wherein the abrasive particles are angular-shaped.
Claim 5
Dependent Claim
25 words
A magnetic recording medium according to claim 1 wherein said abrasive particles have an average particle diameter of between about 0.2 and about 0.5 microns.
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) | 1990-06-01 | 1990-12-01 | 1991-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-01 | 1994-12-01 | 1995-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-01 | 1998-12-01 | 1999-06-02 | $7700.00 | Window Closed / Lapsed |