Patent US3617378A successfully refreshed from Google Patents.
US3617378A
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Magnetic recording media
Assignee: International Business Machines Corp
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Filing: 1969-09-29
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Granted: 1971-11-02
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Expires: 1989-09-29
Abstract
Abstract This invention discloses a magnetic recording medium in the form of a nonconductive substrate having two surfaces, one surface being coated with a magnetic recording material and the other surface being coated with a composition exhibiting selected properties as to its resistivity and as to its coefficient of friction with regard to its use in a media handling system. Also, a media handling system, including such a magnetic recording media, is disclosed.
Inventors
- 👤 Charles K Beck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:52
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; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
15 words
The magnetic record medium defined in claim 1 wherein the conductive particles are carbon black.
Claim 2
Dependent Claim
20 words
The magnetic record medium defined in claim 1 wherein the magnetic layer comprises magnetic particles dispersed in a binder matrix.
Claim 3
Dependent Claim
14 words
The magnetic record medium defined in claim 1 wherein the substrate is a polyester.
Claim 4
Dependent Claim
197 words
A magnetic record medium for use as one of a stacked plurality of such media in a media handling system, said system including a resilient medium actuator for removing a medium from a media stack and a smooth hard transport surface upon which the medium is moved in sliding contact, said record medium comprising: A nonmagnetic substrate having two faces; a magnetic layer covering one face of said substrate; and a wear resistant antistatic and friction controlled coating securely adhered to the second face of said substrate, said coating consisting essentially of conductive particles and particles of nonmagnetic Alpha -Fe2O3 dispersed in a binder matrix of polymeric material, said Alpha -Fe2O3 particles constituting about 8 percent to about 40 percent, by weight, of the said antistatic and friction controlled coating, and said coating having a thickness greater than about 0.1 mil, a coefficient of friction with the resilient medium actuator of at least 0.90, a coefficient of friction with the transport surface of less than 0.35, a coefficient of friction with the magnetic layer of an adjacently stacked magnetic record medium of less than 0.05, and a resistivity no greater than 5 X 108 ohms per square.
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) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |