Patent US4275113A successfully refreshed from Google Patents.
US4275113A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Maxell Ltd
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Filing: 1979-10-17
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Granted: 1981-06-23
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Expires: 1999-10-17
Abstract
Abstract Magnetic recording medium comprising a support or carrier sheet and a magnetic layer formed on one side of the support, wherein there is provided between the support and the magnetic layer at least one intermediate layer of resinous polymeric material including particles of carbon black having large specific surface area and high oil absorption so that electrification of the recording medium can be prevented with good adhesiveness of the magnetic layer to the support.
Inventors
- 👤 Osamu Saito
- 👤 Jozo Shimizu
- 👤 Hiroshi Zaitsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:19
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/73; G11B5/733; G11B5/7334; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
112 words
A magnetic recording medium comprising a carrier sheet consisting of a non magnetic film, at least one adherently bonded intermediate layer formed on the carrier sheet and a magnetic layer formed on the intermediate layer, said intermediate layer being composed of resinous polymeric material including electrically conductive material made of particles of carbon black having a specific surface area of not less than 700 m 2 /g and an oil absorption of not lower than 300 ml (DBP)/100 g, said carbon black being contained in the intermediate layer within the range of 5 to 30% by weight, wherein said electrical conductive material is biased in the intermediate layer towards the magnetic layer.
Claim 2
Dependent Claim
112 words
A magnetic recording medium comprising a carrier sheet consisting of a non magnetic film, at least one adherently bonded intermediate layer formed on the carrier sheet and a magnetic layer formed on the intermediate layer, said intermediate layer being composed of resinous polymeric material including electrically conductive material made of particles of carbon black having a specific surface area of not less than 700 m 2 /g and an oil absorption of not lower than 300 ml (DBP)/100 g, said carbon black being contained in the intermediate layer within the range of 5 to 30% by weight, wherein said electrical conductive material is biased in the intermediate layer towards the magnetic layer.
Claim 3
Dependent Claim
18 words
The magnetic recording medium according to claim 1 wherein said carrier sheet is made of a polyester film.
Claim 4
Dependent Claim
24 words
The magnetic recording medium according to claim 2 wherein the intermediate layer contains a binder which consists essentially of a high molecular weight polyester.
Claim 5
Dependent Claim
27 words
The magnetic recording medium according to claim 1, wherein said intermediate layer is composed of two layers laid together between the carrier sheet and the magnetic layer.
Claim 6
Dependent Claim
22 words
The magnetic recording medium of claim 1 wherein the carbon black has a particle size of not more than about 30 mμ.
Claim 7
Dependent Claim
134 words
A magnetic recording medium comprising a carrier sheet consisting of a non magnetic film, at least one adherently bonded intermediate layer formed on the carrier sheet and a magnetic layer formed on the intermediate layer, said intermediate layer being composed of resinous polymeric material including electrically conductive material made of particles of carbon black having a specific surface area of not less than 700 m 2 /g and an oil absorption of not lower than 300 ml (DBP)/100 g, said carbon black being contained in the intermediate layer within the range of 5 to 30% by weight, wherein said electrical conductive material is biased in the intermediate layer towards the magnetic layer, said magnetic recording medium possessing a decreased surface resistivity and a reinforced bonding force between the magnetic layer and the carrier sheet.
Claim 8
Dependent Claim
134 words
A magnetic recording medium comprising a carrier sheet consisting of a non magnetic film, at least one adherently bonded intermediate layer formed on the carrier sheet and a magnetic layer formed on the intermediate layer, said intermediate layer being composed of resinous polymeric material including electrically conductive material made of particles of carbon black having a specific surface area of not less than 700 m 2 /g and an oil absorption of not lower than 300 ml (DBP)/100 g, said carbon black being contained in the intermediate layer within the range of 5 to 30% by weight, wherein said electrical conductive material is biased in the intermediate layer towards the magnetic layer, said magnetic recording medium possessing a decreased surface resistivity and a reinforced bonding force between the magnetic layer and the carrier sheet.
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) | 1984-06-22 | 1984-12-22 | 1985-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-22 | 1988-12-22 | 1989-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-22 | 1992-12-22 | 1993-06-23 | $7700.00 | Window Closed / Lapsed |