Patent US4568619A successfully refreshed from Google Patents.
US4568619A
Expired / Lapsed
US
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Nonmagnetic particles to improve properties of magnetic recording compositions
Assignee: EIDP Inc
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Filing: 1983-06-09
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Granted: 1986-02-04
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Expires: 2003-06-09
Abstract
Abstract Ferromagnetic recording elements with improved physical properties have from 20 to 50% of the volume of ferromagnetic particles replaced by nonmagnetic particles of a size smaller than the thickness of the magnetic layer.
Inventors
- 👤 Dale M. Hiller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:11
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
53 words
An improved magnetic recording element comprising a support and a magnetic layer on said support, the recording layer containing a binder having dispersed therein solid particles of (a) 50 to 70% ferromagnetic chromium dioxide, and (b) 30 to 50% zinc oxide, these percentages being by volume of the total volume of all particles.
Claim 2
Dependent Claim
53 words
An improved magnetic recording element comprising a support and a magnetic layer on said support, the recording layer containing a binder having dispersed therein solid particles of (a) 50 to 70% ferromagnetic chromium dioxide, and (b) 30 to 50% zinc oxide, these percentages being by volume of the total volume of all particles.
Claim 3
Dependent Claim
17 words
The magnetic recording element of claim 1 wherein said element is in the form of a tape.
References Cited (Backward Citations)
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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) | 1989-02-03 | 1989-08-05 | 1990-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-03 | 1993-08-05 | 1994-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-03 | 1997-08-05 | 1998-02-04 | $7700.00 | Window Closed / Lapsed |