US3823022A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making copy sheets with a concealed image and visual development of same
Assignee: AB Dick Co
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Filing: 1972-04-17
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Granted: 1974-07-09
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Expires: 1992-04-17
Abstract
Abstract A METHOD FOR IMAGING A COPY SHEET WITH A CONCEALED IMAGE AND FOR THE SUBSEQUENT VISUAL DEVELOPMENT OF THE CONCEALED IMAGE, WHEREIN A COPY SHEET IS FIRST IMAGED WITH A LEWIS ACID TO PROVIDE A CONCEALED IMAGE AND THE RESULTING CONCEALED IMAGE IS SUBSEQUENTLY MARKED WITH A MARKING COMPOSITION CONTAINING A MIXTURE OF A WAX AND A LEUCO CYE INTERMEDIATE WHICH IS CAPABLE OF REACTION WITH THE LEWIS CID FORMING THE CONCEALED IMAGE TO PRODUCE COLOR OF HIGH INTENSITY.
Inventors
- 👤 R Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 00:47
CPC Classifications
G; G09; G09B; G09B3/00; G09B3/06; G09B3/08; G09B3/085; B; B41; B41M; B41M3/00; B41M3/001; Y; Y10; Y10S; Y10S101/00; Y10S101/29
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) | 1977-07-08 | 1978-01-07 | 1978-07-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-08 | 1982-01-07 | 1982-07-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-08 | 1986-01-07 | 1986-07-09 | $7700.00 | Window Closed / Lapsed |