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US3767401A
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Regeneration of photographic bleach/fix baths
Assignee: 3M Co
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Filing: 1971-12-15
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Granted: 1973-10-23
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Expires: 1991-12-15
Abstract
Abstract Depleted photographic bleach/fix baths which include bleaching agents (such as the iron III complex of ethylenediaminetetraacetic acid) and a silver halide solvent are regenerated by addition to a recycled stream thereof of an iron, cobalt and copper-free regenerating solution which includes a polycarboxylic acid, a silver halide solvent, and an organic bleach-enhancing compound which includes at least one atom which is different from carbon, hydrogen and nitrogen.
Inventors
- 👤 N Newman
- 👤 R Fisch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:18
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/395; G03C5/3952
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
12 words
The process according to claim 1 wherein said bleach-enhancing compound is thiosemicarbazide.
Claim 2
Dependent Claim
12 words
The process according to claim 1 wherein said bleach-enhancing compound is thiocarbohydrazide.
Claim 3
Dependent Claim
17 words
The process according to claim 1 wherein said bleaching agent is iron (III) complex of ethylenediaminetetraacetic acid.
Claim 4
Dependent Claim
18 words
The process according to claim 1 wherein said bleaching agent is the iron (III) salt of nitrilotriacetic acid.
Claim 5
Dependent Claim
15 words
The process according to claim 1 wherein said regenerating composition is in aqueous solution form.
Claim 6
Dependent Claim
87 words
A regenerating composition for regenerating depleted photographic bleach/fix working baths which contains a bleaching agent selected from the group consisting of ferric, cobaltic and cupric complex salts of an acid selected from the group consisting of polycarboxylic acids, hydroxypolycarboxylic acids and aminopolycarboxylic acids, and a silver halide solvent, said composition being essentially free of iron, cobalt and copper and including a sIlver halide solvent, said acid of said bleaching agent, and an organic bleach-enhancing compound which includes at least one sulfur or at least one nitrogen atom.
Claim 7
Dependent Claim
11 words
The composition of claim 7 wherein said bleach-enhancing compound is thiosemicarbazide.
Claim 8
Dependent Claim
11 words
The composition of claim 7 wherein said bleach-enhancing compound is thiocarbohydrazide.
Claim 9
Dependent Claim
16 words
The composition of claim 7 wherein said bleaching agent is iron (III) complex of ethylenediaminetetraacetic acid.
Claim 10
Dependent Claim
17 words
The composition of claim 7 wherein said bleaching agent is the iron (III) salt of nitrilotriacetic acid.
Claim 11
Dependent Claim
13 words
The composition of claim 7 wherein said composition is in aqueous solution form.
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) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |