US3824128A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording medium
Assignee: Fujifilm Holdings Corp
•
Filing: 1972-05-24
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Granted: 1974-07-16
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Expires: 1992-05-24
Abstract
Abstract A MAGNETIC RECORDING MEDIUM HAVING A MAGNETIC RECORDING LAYER IN WHICH IS DISPERSED IN A BINDER A FERROMAGNETIC POWDER COMPRISING A MIXTURE OF AN IRON OXIDE POWDER AND A CHROMIUM DIOXIDE POWDER IN A WEIGHT RATIO OF 1:4 TO 4:1 RESPECTIVELY, AND POSSESSING IMPROVED SENSITIVITY TO SHORT WAVE-LENGHT SIGNALS, PARTICULARLY EVEN AFTER BEING SUBJECT TO HEAT.
Inventors
- 👤 G Akashi
- 👤 T Kitamoto
- 👤 M Fujiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:57
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/68; G11B5/70; G11B5/706; G11B5/70626; G11B5/70636; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/257; Y10T428/31504; Y10T428/31786; Y10T428/31971
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) | 1977-07-15 | 1978-01-14 | 1978-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-15 | 1982-01-14 | 1982-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-15 | 1986-01-14 | 1986-07-16 | $7700.00 | Window Closed / Lapsed |