Patent US5322438A successfully refreshed from Google Patents.
US4576899A
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Method for enhancing apparent photospeed of diazonium plates by using thiocyanate to insolubilize diazonium compound after photolysis
Assignee: IMPERIAL METAL & CHEMICAL COMPANY 3400 ARAMINGO AVENUE PHILADELPHIA PENNSYLVANIA 19134 A CORP OF PA
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Filing: 1984-05-01
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Granted: 1986-03-18
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Expires: 2004-05-01
Abstract
Abstract A developer is provided for lithographic plates or the like having a layer including a diazonium material, which developer enhances the effectiveness of the photolysis to which the plate had been subjected, with the result that the exposure time needed for the plate is substantially reduced. The developer, which thus enhances the apparent photospeed of the plate, includes an insolubilizing reactant that reacts with diazonium groups of diazonium materials on the plate that were not removed by photolysis during exposure in order to decrease the solubility of the diazonium material.
Inventors
- 👤 Luigi Amariti
- 👤 Llandro C. Santos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:05
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/016
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
194 words
A method for enhancing the apparent photospeed of a plate having a layer including a diazonium material, comprising: selectively photolyzing a plate to define image areas, said plate having a layer including a light-sensitive, negative-working diazonium material, said selective photolyzing including underexposing the diazonium material at the image areas, said underexposing including removing some, but not all, diazonium groups from the diazonium material; applying a developer composition to the selectively photolyzed and underexposed plate, wherein said developer composition includes substantial amounts of water and an insolubilizing reactant, said insolubilizing reactant being a thiocyanate salt that is present in an amount sufficient to enhance the apparent photospeed of the plate; reacting the insolubilizing reactant of the applied developer composition with unphotolyzed diazonium groups of the diazonium material at the image areas in order to reduce the solubility of the selectively photolyzed diazonium material; and removing unphotolyzed diazonium material from the plate while substantially retaining the photolyzed and reacted diazonium material on the plate at the image areas, wherein said unphotolyzed diazonium material is soluble in the developer composition and said photolyzed and reacted diazonium material at the image areas is insoluble in the developer composition.
Claim 2
Independent Claim
194 words
A method for enhancing the apparent photospeed of a plate having a layer including a diazonium material, comprising: selectively photolyzing a plate to define image areas, said plate having a layer including a light-sensitive, negative-working diazonium material, said selective photolyzing including underexposing the diazonium material at the image areas, said underexposing including removing some, but not all, diazonium groups from the diazonium material; applying a developer composition to the selectively photolyzed and underexposed plate, wherein said developer composition includes substantial amounts of water and an insolubilizing reactant, said insolubilizing reactant being a thiocyanate salt that is present in an amount sufficient to enhance the apparent photospeed of the plate; reacting the insolubilizing reactant of the applied developer composition with unphotolyzed diazonium groups of the diazonium material at the image areas in order to reduce the solubility of the selectively photolyzed diazonium material; and removing unphotolyzed diazonium material from the plate while substantially retaining the photolyzed and reacted diazonium material on the plate at the image areas, wherein said unphotolyzed diazonium material is soluble in the developer composition and said photolyzed and reacted diazonium material at the image areas is insoluble in the developer composition.
Claim 3
Dependent Claim
37 words
The method according to claim 1, wherein said selective photolyzing step includes subjecting the diazonium material to actinic radiation for a period of time substantially less than that needed to substantially fully photolyze the exposed diazonium material.
Claim 4
Dependent Claim
25 words
The method according to claim 1, wherein said selective photolyzing step is preceded by a step of providing a plate having a stabilized diazonium material.
Claim 5
Dependent Claim
32 words
The method according to claim 1, wherein said selective photolyzing step is preceded by a step of providing a plate having a stabilized diazonium material that is stabilized with a purine derivative.
Claim 6
Dependent Claim
21 words
The method according to claim 1, wherein said reacting step includes reacting --NN.Cl groups with --SCN groups to form --NN.SCN moieties.
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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) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |