US3632341A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic developer
Assignee: Northrop Grumman Guidance and Electronics Co Inc
•
Filing: 1970-03-13
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Granted: 1972-01-04
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Expires: 1990-03-13
Abstract
Abstract An extended range fast-working photographic developer solution containing a hydroxybenzene compound and a 3-pyrazolidone compound in about a 1:1 weight ratio, and having a highly alkaline pH is disclosed.
Inventors
- 👤 Arthur Zacchia
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:45
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/30; Y; Y10; Y10S; Y10S430/00; Y10S430/129
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
14 words
A photographic developer of claim 1 wherein said hydroxybenzene compound comprises a dihydroxybenzene compound.
Claim 2
Dependent Claim
12 words
A photographic developer of claim 2 wherein said dihydroxybenzene compound comprises hydroquinone.
Claim 3
Dependent Claim
12 words
A photographic developer of claim 3 wherein said 3-pyrazolidone compound comprises 1-phenyl-3-pyrazolidone.
Claim 4
Dependent Claim
27 words
A photographic developer of claim 4 wherein said alkali is present in an amount sufficient to produce a developer pH of from about 10.5 to about 11.0.
Claim 5
Dependent Claim
21 words
A photographic developer of claim 5 wherein said 1-phenyl-3-pyrazolidone and said hydroquinone are present in a weight ratio of about 1:1.
Claim 6
Dependent Claim
14 words
A photographic developer of claim 6 whereiN said developer also contains a fog restrainer.
Claim 7
Dependent Claim
11 words
A photographic developer of claim 7 which also contains an antioxidant.
Claim 8
Dependent Claim
25 words
A photographic developer of claim 8 wherein said alkali is present in an amount sufficient to produce pH of about 11 in said photographic developer.
Claim 9
Dependent Claim
31 words
A photographic developer of claim 9 wherein said alkali comprises sodium metaborate and is present in amount of from about 30 to about 110 grams per liter of photographic developer solution.
Claim 10
Dependent Claim
27 words
A photographic developer replenisher containing the following, based on 1 liter of aqueous solution: 1-phenyl-3-pyrazolidone about 2.75 grams hydroquinone about 3.9 grams alkali to pH about 9.5-11.25.
Claim 11
Dependent Claim
33 words
A photographic developer replenisher of claim 11 having the following formulation: grams/liter1-phenyl-3-pyrazolidone about 2.5 hydroquinone about 3.9 sodium tetraborate about 2.5 sodium sulfite about 85 sodium metaborate about 100 water to 1 liter.
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) | 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 |