US3632512A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing magnetically responsive carrier particles
Assignee: Eastman Kodak Co
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Filing: 1969-02-17
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Granted: 1972-01-04
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Expires: 1989-02-17
Abstract
Abstract FERROMAGNETIC CARRIER PARTICLES HAVING UNIFORM SURFACE AND TRIBOELETRIC PROPERTIES CAN BE PREPARED BY TREATMENT OF COMMERCIAL IRON POWDERS IN AN AQUEOUS ACID SOLUTION, FOLLOWED BY REMOVAL OF ACID, RINSING AND CONTROLLED DRYING TO INCLUDE OR EXCLUDE OXIDATION. THE RESULTANT PARTICLES CAN SUBSEQUENTLY BE OVERCOATED WITH A THIN, UNIFORM, CONTINUOUS FILM OR A NONFERROUS MATERIAL SUCH AS A METAL OR A RESINOUS MATERIAL. THESE CARRIER PARTICLES ARE USEFUL FOR APPLYING ELECTROSCOPIC TONER MATERIAL TO ELECTROSTATIC LATENT IMAGES.
Inventors
- 👤 Howard A Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 08:18
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/113; G03G9/1131; G03G9/107; G03G9/1075
Claims Analysis
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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) | 1975-01-03 | 1975-07-05 | 1976-01-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-03 | 1979-07-05 | 1980-01-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-03 | 1983-07-05 | 1984-01-04 | $7700.00 | Window Closed / Lapsed |