Patent US3989864A successfully refreshed from Google Patents.
Patent US4444842A successfully refreshed from Google Patents.
US4444842A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1982-03-16
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Granted: 1984-04-24
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Expires: 2002-03-16
Abstract
Abstract A magnetic recording medium is disclosed which is comprised of a non-magnetic support base having a magnetic layer on one surface and a silicone oil layer formed on the opposite surface. The silicone oil layer does not produce dropouts and eliminates scraping and therefore eliminates dust particles that collect and build up in the area of the magnetic head. The silicone layer is formed from a silicone-containing compound having a viscosity of at least 6,000 centistokes at 25° C.
Inventors
- 👤 Nobutaka Yamaguchi
- 👤 Nobuo Tsuji
- 👤 Yasutoshi Okuzawa
- 👤 Norio Nasu
- 👤 Masaaki Fujiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:16
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/72; G11B5/725; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/27; Y10T428/31504; Y10T428/31652; Y10T428/31663
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
61 words
A magnetic recording medium, comprising: a non-magnetic support base having a first and second side; a magnetic layer positioned on said first side of said non-magnetic support base; and a silicone oil layer consisting essentially of a high-viscosity silicone oil having a viscosity of at least 6,000 centistokes at 25° C., formed on said second surface of said non-magnetic support base.
Claim 2
Dependent Claim
61 words
A magnetic recording medium, comprising: a non-magnetic support base having a first and second side; a magnetic layer positioned on said first side of said non-magnetic support base; and a silicone oil layer consisting essentially of a high-viscosity silicone oil having a viscosity of at least 6,000 centistokes at 25° C., formed on said second surface of said non-magnetic support base.
Claim 3
Dependent Claim
20 words
A magnetic recording medium as claimed in claim 1, wherein said viscosity is at least 100,000 centistokes at 25° C.
Claim 4
Dependent Claim
36 words
A magnetic recording medium as claimed in any of claims 1 or 2, wherein said silicone oil is an oil compound selected from the group of compounds consisting of dimethyl polysiloxane, methylphenyl polysiloxane or fluorine-containing polysiloxane.
Claim 5
Dependent Claim
26 words
A magnetic recording medium as claimed in claim 3, wherein said silicone oil is a dimethyl polysiloxane having the formula ##STR2## wherein n is an integer.
Claim 6
Dependent Claim
34 words
A magnetic recording medium as claimed in claim 1, wherein said silicone oil is positioned on said second side of said non-magnetic support base in an amount of 0.5 to 20 mg/m 2 .
Claim 7
Dependent Claim
32 words
A magnetic recording medium as claimed in claim 1, wherein said silicone oil layer consists of a high viscosity silicone oil having a viscosity of at least 6,000 centistokes at 25° C.
Claim 8
Dependent Claim
20 words
A magnetic recording medium as claimed in claim 1, wherein said magnetic layer comprises ferromagnetic particles dispersed in a binder.
Claim 9
Dependent Claim
20 words
A magnetic recording medium as claimed in claim 7, wherein said ferromagnetic particles are Co-containing γ-Fe 2 O 3 .
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) | 1987-04-24 | 1987-10-24 | 1988-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-04-24 | 1991-10-24 | 1992-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-04-24 | 1995-10-24 | 1996-04-24 | $7700.00 | Window Closed / Lapsed |