Patent US3958994A successfully refreshed from Google Patents.
US3958994A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photosensitive diazo steel lithoplate structure
Assignee: CNA Holdings LLC
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Filing: 1974-08-26
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Granted: 1976-05-25
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Expires: 1994-08-26
Abstract
Abstract A lithographic printing plate structure and method of manufacture, in which a support sheet of steel, normally subject to corrosion in a lithographic environment, such as a mild steel, is coated, preferably on both sides, with aluminum, zinc or an aluminum-zinc alloy to a thickness of about 1 to 3 mils, a polyvinyl phosphonic acid is disposed on the metal coating and a negative working diazo photo-sensitive layer is applied over the polyvinyl phosphonic acid coating.
Inventors
- 👤 Leo S. Burnett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 18:51
CPC Classifications
B; B32; B32B; B32B15/00; B32B15/01; B32B15/012; B32B15/013; B41; B41N; B41N1/00; B41N1/04; B41N1/08; B41N1/083; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/926; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12542; Y10T428/12549; Y10T428/12736; Y10T428/1275; Y10T428/12757; Y10T428/12771; Y10T428/12861; Y10T428/12951; Y10T428/12972; Y10T428/31504; Y10T428/31678; Y10T428/31692
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
123 words
A lithographic printing plate structure, comprising a support sheet of steel, normally subject to corrosion in a lithographic environment, a metallurgically bonded coating of aluminum-zinc alloy in which the alloy comprises about 25 to 70% aluminum and about 75 to 30% zinc, on at least one side of said sheet of steel, said coating having a thickness in the range of about 0.5 to 3 mils, a coating of a polyvinyl phosphonic acid directly on said coating, and, directly on said polyvinyl phosphonic acid coating, a photosensitive layer comprising a diazo compound which upon exposure to actinic light provides photo-hardened areas in the exposed areas of the layer, whereby upon development of the layer with a solvent only the unexposed areas are removed.
Claim 2
Dependent Claim
123 words
A lithographic printing plate structure, comprising a support sheet of steel, normally subject to corrosion in a lithographic environment, a metallurgically bonded coating of aluminum-zinc alloy in which the alloy comprises about 25 to 70% aluminum and about 75 to 30% zinc, on at least one side of said sheet of steel, said coating having a thickness in the range of about 0.5 to 3 mils, a coating of a polyvinyl phosphonic acid directly on said coating, and, directly on said polyvinyl phosphonic acid coating, a photosensitive layer comprising a diazo compound which upon exposure to actinic light provides photo-hardened areas in the exposed areas of the layer, whereby upon development of the layer with a solvent only the unexposed areas are removed.
Claim 3
Dependent Claim
13 words
A structure in accordance with claim 1 wherein the steel is mild steel.
Claim 4
Dependent Claim
21 words
A structure in accordance with claim 1 wherein the metal coating is disposed on both sides of the sheet of steel.
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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) | 1979-05-25 | 1979-11-24 | 1980-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-05-25 | 1983-11-24 | 1984-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-05-25 | 1987-11-24 | 1988-05-25 | $7700.00 | Window Closed / Lapsed |