Patent US4418185A successfully refreshed from Google Patents.
Patent EP0678380A2 successfully refreshed from Google Patents.
EP0678380A2
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EP
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Laser-imageable printing members for wet lithographic printing
Assignee: Presstek LLC
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Filing: 1995-04-10
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Granted: —
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Expires: 2015-04-10
Abstract
Abstract Lithographic printing constructions and methods of imaging them[ are disclosed]. The constructions include a grained-metal substrate, a protective layer that' can also serve as an adhesion-promoting primer, and an ablatable oleophilic surface layer. In operation, imagewise pulses from an imaging laser interact with the surface layer, causing ablation thereof and, probably, inflicting some damage to the underlying protective layer as well. The imaged plate may then be subjected to a solvent that eliminates the exposed protective layer, but which does no damage either to the surface layer or to the unexposed protective layer lying thereunder.
Inventors
- 👤 Thomas E. Lewis
- 👤 Kenneth R. Cassidy
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 18:37
CPC Classifications
B; B41; B41C; B41C1/00; B41C1/10; B41C1/1008; B41C1/1033
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
50 words
A lithographic printing member directly imageable by laser discharge, the member comprising: a. an ink-accepting first layer characterized by ablative absorption of imaging radiation; b. a second layer underlying the first layer, the second layer being at least partially soluble in a cleaning solvent; and c. a hydrophilic metal substrate.
Claim 2
Dependent Claim
50 words
A lithographic printing member directly imageable by laser discharge, the member comprising: a. an ink-accepting first layer characterized by ablative absorption of imaging radiation; b. a polymeric, hydrophilic second layer underlying the first layer and not being characterised by ablative absorption of imaging radiation; and c. a hydrophilic metal substrate.
Claim 3
Dependent Claim
104 words
The member of claim 1 or claim 2 wherein the second layer is characterized by any one of the following: a. at least partial solubility in water; b. at least partial solubility in water combined with a co-solvent; c. at least partial solubility in water combined with a co-solvent selected from the group consisting of alcohols and glycol ethers; d. at least partial solubility in water pH-buffered to acid or neutral pH; e. being present in sufficient thickness to prevent damage to the substrate from exposure to imaging laser radiation; or f. being a crosslinked, polymeric reaction product of polyvinyl alcohol and hydrolyzed tetraethylorthosilicate.
Claim 4
Dependent Claim
40 words
The member of claim 1 or claim 2 wherein the second layer is either (when dependent on claim 1) polymeric and/or (when dependent on claim 1 or claim 2) a primer that anchors the first layer [and] to the substrate.
Claim 5
Dependent Claim
18 words
The member of claim 1 wherein the substrate is either aluminium or chromium having a textured surface topography.
Claim 6
Dependent Claim
30 words
The member of claim 1 or claim 2 wherein the topmost layer comprises a substance that absorbs any one of: a. near-IR radiation; b. ultraviolet radiation; or c. visible radiation.
Claim 7
Dependent Claim
100 words
The member of claim 1 wherein any one of:: a. the second layer is hydrophilic; b. the second layer is not characterised by ablative absorption of imaging radiation; c. the second layer is selected from the group consisting of polyvinylphosphonic acid, polyvinylmethylphosphonic acid, phosphoric acid esters of polyvinyl alcohol, polyvinylsulfonic acid, polyvinylbenzenesulfonic acid, sulfuric acid esters of polyvinyl alcohol, and acetals of polyvinyl alcohols formed by reaction with a sulfonated aliphatic aldehyde; d. the ink-accepting first layer comprises a nitrocellulose compound; or e. the second layer is selected from the group consisting of polyvinyl pyrrolidone, cellulose ethers, casein, and gelatins.
Claim 8
Independent Claim
148 words
A method of imaging a lithographic printing member comprising the steps of: a. providing a lithographic printing member comprising: i an ink-accepting topmost layer ablatable by laser radiation; ii. a second layer underlying the first layer, the second layer being at least partially soluble in a cleaning solvent; and iii. a hydrophilic metal substrate, b. spacing at least one laser source opposite the printing member; c. guiding the output of the at least one laser to focus on the printing member, d. causing relative movement between the guiding means and the support means to effect a scan of the printing member by the laser output; and e. selectively exposing, in a pattern representing an image, the printing member to the laser output during the course of the scan so as to remove at least the top layer, thereby directly producing on the plate an array of image features.
Claim 9
Dependent Claim
15 words
The method of claim 8 wherein the second layer of the printing member is hydrophilic.
Claim 10
Dependent Claim
29 words
The method of claim 8 further comprising the step of subjecting the printing member to a cleaning solvent to remove portions of the second layer lying within image features.
Claim 11
Dependent Claim
38 words
The method of claim 8 wherein the cleaning solvent is water which may include a co-solvent possibly selected from the group consisting of alcohols and glycol ethers, and the water may be pH-buffered to acid or neutral pH.
References Cited (Backward Citations)
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