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US3630735A
Expired / Lapsed
US
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Method for fixing light-sensitive free radical photographic materials with heavy metal salts
Assignee: Keuffel and Esser Co
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Filing: 1967-08-23
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Granted: 1971-12-28
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Expires: 1987-08-23
Abstract
Abstract Images formed in free radical photosensitive materials comprising organic halogen-containing photoactivators capable of generating halogen free radicals upon exposure to light are fixed by treatment with aqueous solutions of reducing heavy metal salts.
Inventors
- 👤 Kohei Itano
- 👤 Shoichiro Hoshino
- 👤 Akira Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:35
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/56; G03C1/00; G03C1/675
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
47 words
The improvement according to claim 1 wherein said aqueous solution comprises between about 5 and 40 percent of a heavy metal salt selected from the group consisting of stannous chloride, stannous bromide, stannous iodide, titanic chloride, ferrous sulfate, titanic sulfate, vanadous sulfate, chromous chloride and chromous sulfate.
Claim 2
Dependent Claim
32 words
The improvement according to claim 2 wherein said aqueous solution additionally comprises between about 2 and 10 percent of an organic reducing agent selected from the group consisting of metol and hydroquinone.
Claim 3
Dependent Claim
33 words
The improvement according to claim 1 wherein said treating step comprises wetting said composition with said aqueous solution and drying the resulting wetted composition at a temperature between about 100* - 180* C.
References Cited (Backward Citations)
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 |