US3630910A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1968-01-12
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Granted: 1971-12-28
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Expires: 1988-01-12
Abstract
Abstract BY INCORPORATING FINE ABRASIVE PARTICLES IN A MAGNETIC LAYER CONTAINING FERROMAGNETIC POWDER IN A BINDER ON A MAGNETIC RECORDING MEDIUM, THE SURFACE OF A RECORDING AND REPRODUCING HEAD CAN BE MAINTAINED IN A SMOOTH CONDITION. THE ABRASVIE PARTICLES MAY ALSO FORM THE OUTER SURFACE OF THE MAGNETIC LAYER.
Inventors
- 👤 Goro Akashi
- 👤 Masaaki Fujiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:25
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/708; G11B5/7085
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |