US4666754A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: TDK Corp
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Filing: 1985-06-20
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Granted: 1987-05-19
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Expires: 2005-06-20
Abstract
Abstract A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on the substrate, and a top coating layer formed on the magnetic recording layer, wherein the top coating layer contains a fine particulate pigment at its surface, and the surface roughness (R20) of the top coating layer is less than 400 Å.
Inventors
- 👤 Hiroyuki Arioka
- 👤 Hideki Ishizaki
- 👤 Toshiaki Ide
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 04:12
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/25
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
78 words
A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on the substrate, and a top coating layer formed on the magnetic recording layer, wherein the top coating layer contains a fine particulate pigment having a particle size less than 200 Å at its surface in an amount of from 15,000 to 1,000,000 particles/100 μm 2 , and the surface roughness (R20) of the top coating layer is between 20 and less than 400 Å.
Claim 2
Dependent Claim
78 words
A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on the substrate, and a top coating layer formed on the magnetic recording layer, wherein the top coating layer contains a fine particulate pigment having a particle size less than 200 Å at its surface in an amount of from 15,000 to 1,000,000 particles/100 μm 2 , and the surface roughness (R20) of the top coating layer is between 20 and less than 400 Å.
Claim 3
Dependent Claim
16 words
The magnetic recording medium according to claim 1, wherein the top coating layer contains an antioxidant.
Claim 4
Dependent Claim
16 words
The magnetic recording medium according to claim 2, wherein the antioxidant is of radiation curable type.
Claim 5
Dependent Claim
31 words
The magnetic recording medium according to claim 1, wherein the top coating layer contains at least one member selected from the group consisting of a monomer, an oligomer and a polymer.
Claim 6
Dependent Claim
16 words
The magnetic recording medium according to claim 1, wherein the top coating layer contains a lubricant.
Claim 7
Dependent Claim
25 words
The magnetic recording medium according to claim 1, wherein the magnetic recording layer is composed of a ferromagnetic alloy powder dispersed in a resin binder.
Claim 8
Dependent Claim
20 words
The magnetic recording medium according to claim 1, wherein the magnetic recording layer is composed of a ferromagnetic thin film.
References Cited (Backward Citations)
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US4520070A
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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) | 1990-05-18 | 1990-11-17 | 1991-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-18 | 1994-11-17 | 1995-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-18 | 1998-11-17 | 1999-05-19 | $7700.00 | Window Closed / Lapsed |