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US4720413A
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US
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Magnetic recording medium having a back coat layer
Assignee: Victor Company of Japan Ltd
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Filing: 1986-07-21
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Granted: 1988-01-19
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Expires: 2006-07-21
Abstract
Abstract A magnetic recording medium which comprises a non-magnetic support, a magnetic recording layer formed on one side of the support, and a back coat layer formed on the other side. The back coat layer is made of a dispersion, in a binder resin, of non-magnetic particles on which there is adsorbed carbon black having an average size not larger than 100 millimicrons and a specific surface area not less than 30 m 2 /g.
Inventors
- 👤 Akira Horiguchi
- 👤 Isao Sasaki
- 👤 Hirokazu Moriizumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 04:52
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/735; G11B5/7356; G11B5/7358; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/24; Y10T428/24355; Y10T428/24372; Y10T428/25
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
94 words
In a magnetic recording medium which comprises a non-magnetic support, a magnetic recording layer formed on one side of the support, and a back coat layer formed on the other side of the support, the improvement in that said back coat layer is made of a dispersion, in a resin binder, of non-magnetic particles which have a Mohs hardness of from 2.5 to 10 and which have adsorbed thereon carbon black having an average particle size not larger than 100 millimicrometers and a specific surface area of not less than 30 m 2 /g.
Claim 2
Dependent Claim
94 words
In a magnetic recording medium which comprises a non-magnetic support, a magnetic recording layer formed on one side of the support, and a back coat layer formed on the other side of the support, the improvement in that said back coat layer is made of a dispersion, in a resin binder, of non-magnetic particles which have a Mohs hardness of from 2.5 to 10 and which have adsorbed thereon carbon black having an average particle size not larger than 100 millimicrometers and a specific surface area of not less than 30 m 2 /g.
Claim 3
Dependent Claim
21 words
A magentic recording medium according to claim 1, wherein the Mohs hardness is in the range of from 6 to 10.
Claim 4
Dependent Claim
34 words
A magnetic recording medium according to claim 1, wherein the back coat layer is made of the carbon black-adsorbing non-magnetic particles and the resin binder in a ratio by weight of 1/10 to 10/1.
Claim 5
Dependent Claim
22 words
A magnetic recording medium according to claim 1, wherein said non-magnetic particles have an average size of from 0.01 to 2 micrometers.
Claim 6
Dependent Claim
24 words
A magnetic recording medium according to claim 1, wherein the back coat layer has a centerline average roughness of from 0.005 to 0.1 micrometer.
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) | 1991-01-18 | 1991-07-20 | 1992-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-18 | 1995-07-20 | 1996-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-18 | 1999-07-20 | 2000-01-19 | $7700.00 | Window Closed / Lapsed |