US3607275A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diazo-type material
Assignee: Keuffel and Esser Co
•
Filing: 1968-11-27
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Granted: 1971-09-21
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Expires: 1988-11-27
Abstract
Abstract Diazo-type images obtained from copying material comprising pamino benzene diazonium compounds and 2,3-dihydroxypyridine are shifted from red to blue color shades by including a watersoluble zinc salt with the diazonium compound in a ratio of at least about 2 to 1.
Inventors
- 👤 Oskar Sus
- 👤 Georg Werner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:12
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/52; G03C1/61
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
52 words
The method according to claim 1 wherein said composition further comprises said 2,3-dihydroxy-pyridine and sufficient acid stabilizer to prevent dye-forming coupling under normal conditions, and wherein said coupling step comprises alkalizing said composition to thereby neutralize said acid stabilizer and form a condition of pH in said composition conducive to dye formation.
Claim 2
Dependent Claim
33 words
The method according to claim 1 wherein said composition consists essentially of said diazonium compound and said zinc salt, and said coupling step comprises contacting said material with a solution comprising said 2,3-dihydroxy-pyridine.
Claim 3
Dependent Claim
23 words
The method according to claim 1 wherein said diazonium compound is: a p-amino benzene diazonium compound and said zinc salt is zinc chloride.
Claim 4
Dependent Claim
23 words
The mEthod according to claim 1 wherein said diazonium compound is selected from the group consisting of 3-alkoxy-and 2, 5-dialkoxy-p-amino benzene diazonium compounds.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |