Patent US3942985A successfully refreshed from Google Patents.
US3942985A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High contrast, rapid access, air stable, regenerable iron chelate developer solutions
Assignee: 3M Co
•
Filing: 1975-03-28
•
Granted: 1976-03-09
•
Expires: 1995-03-28
Abstract
Abstract High contrast, rapid access, air stable, regenerable iron chelate developer solutions comprising at least two developer materials, at least one selected from each group comprising:
Inventors
- 👤 Norman Newman
- 👤 Richard S. Fisch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 03:11
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C5/29; G03C5/30; Y; Y10; Y10S; Y10S430/00; Y10S430/164
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
46 words
An aqueous, high-contrast, air-stable, rapid access, non-fixing developer solution which comprises a. at least one iron chelate developer and b. at least one compound from the group of ascorbic acid, sugar-type derivatives of ascorbic acid and stereoisomers and diastereoisomers of ascorbic acid and its sugar-type derivatives.
Claim 2
Dependent Claim
46 words
An aqueous, high-contrast, air-stable, rapid access, non-fixing developer solution which comprises a. at least one iron chelate developer and b. at least one compound from the group of ascorbic acid, sugar-type derivatives of ascorbic acid and stereoisomers and diastereoisomers of ascorbic acid and its sugar-type derivatives.
Claim 3
Dependent Claim
20 words
The developer solution of claim 1 wherein the at least one compound is selected from ascorbic acid and isoascorbic acid.
Claim 4
Dependent Claim
21 words
The developer solution of claim 1 wherein the iron chelate developer is selected from ferrous ethylenediaminetetraacetic acid and ferrous diethylenetriaminepentaacetic acid.
Claim 5
Dependent Claim
20 words
The developer of claim 2 wherein the iron chelate developer is selected from ferrous ethylenediaminetetraacetic acid and ferrous diethylenetriaminepentaacetic acid.
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) | 1979-03-09 | 1979-09-08 | 1980-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-09 | 1983-09-08 | 1984-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-09 | 1987-09-08 | 1988-03-09 | $7700.00 | Window Closed / Lapsed |