Lithographic printing plates utilizing an oleophilic imaging layer
First Claim
1. A lithographic printing plate that is sensitive to infrared radiation and that can be imaged using a laser emitting in the infrared to form a lithographic printing surface without the use of an alkaline developing solution, but which plate is also roomlight handleable and non-photosensitive,said printing plate consisting essentially of a support having a porous hydrophilic surface and an oleophilic imaging layer overlying said porous hydrophilic surface, said imaging layer comprising an oleophilic, roomlight-handleable, infrared radiation-absorbing, heat-sensitive, film-forming composition which is readily removable from said porous hydrophilic surface prior to imagewise exposure by peeling or rubbing and which is adapted to form a lithographic printing surface as a result of imagewise exposure to absorbable infrared radiation by means of a laser and subsequent removal of the non-exposed areas to reveal the underlying porous hydrophilic surface;
- said imagewise exposure effecting localized generation of heat in the exposed areas of said imaging layer that is insufficient to remove by ablation all imaging layer material in said exposed areas but sufficient to cause said exposed areas to interact with said porous hydrophilic surface and bond strongly thereto so as to provide a durable oleophilic image that is useful in lithographic printing.
10 Assignments
0 Petitions
Accused Products
Abstract
A lithographic printing plate is comprised of a support having a porous hydrophilic surface, such as grained and anodized aluminum, and an oleophilic imaging layer overlying the porous hydrophilic surface. The imaging layer is comprised of an oleophilic, radiation-absorbing, heat-sensitive, film-forming composition which is readily removable from the porous hydrophilic surface prior to imagewise exposure and which is adapted to form a lithographic printing surface as a result of imagewise exposure to absorbable electromagnetic radiation and subsequent removal of the non-exposed areas to reveal the underlying porous hydrophilic surface. Examples of suitable techniques for removing the non-exposed areas include contact with printing ink on the press, removal by lamination and peel development steps and removal by use of an integral stripping layer.
49 Citations
20 Claims
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1. A lithographic printing plate that is sensitive to infrared radiation and that can be imaged using a laser emitting in the infrared to form a lithographic printing surface without the use of an alkaline developing solution, but which plate is also roomlight handleable and non-photosensitive,
said printing plate consisting essentially of a support having a porous hydrophilic surface and an oleophilic imaging layer overlying said porous hydrophilic surface, said imaging layer comprising an oleophilic, roomlight-handleable, infrared radiation-absorbing, heat-sensitive, film-forming composition which is readily removable from said porous hydrophilic surface prior to imagewise exposure by peeling or rubbing and which is adapted to form a lithographic printing surface as a result of imagewise exposure to absorbable infrared radiation by means of a laser and subsequent removal of the non-exposed areas to reveal the underlying porous hydrophilic surface; - said imagewise exposure effecting localized generation of heat in the exposed areas of said imaging layer that is insufficient to remove by ablation all imaging layer material in said exposed areas but sufficient to cause said exposed areas to interact with said porous hydrophilic surface and bond strongly thereto so as to provide a durable oleophilic image that is useful in lithographic printing.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A lithographic printing plate that is sensitive to infrared radiation and that can be imaged using a laser emitting in the infrared to form a lithographic printing surface without the use of an alkaline developing solution, but which plate is also roomlight handleable and non-photosensitive,
said printing plate consisting essentially of a support having a porous hydrophilic surface, an oleophilic imaging layer overlying said porous hydrophilic surface, and an integral stripping layer overlying said imaging layer, said imaging layer comprising an oleophilic, roomlight-handleable, infrared radiation-absorbing, heat-sensitive, film-forming composition which is readily removable from said porous hydrophilic surface prior to imagewise exposure by peeling or rubbing and which is adapted to form a lithographic printing surface as a result of imagewise exposure to absorbable infrared radiation by means of a laser and subsequent removal of the non-exposed areas to reveal the underlying porous hydrophilic surface; - said imagewise exposure effecting localized generation of heat in the exposed areas of said imaging layer that is insufficient to remove by ablation all imaging layer material in said exposed areas but sufficient to cause said exposed areas to interact with said porous hydrophilic surface and bond strongly thereto so as to provide a durable oleophilic image that is useful in lithographic printing;
said stripping layer being transparent to said electromagnetic radiation and adapted to be peeled away from said imaging layer with said non-exposed areas adhering thereto while said exposed areas remain strongly bonded to said porous hydrophilic surface. - View Dependent Claims (20)
- said imagewise exposure effecting localized generation of heat in the exposed areas of said imaging layer that is insufficient to remove by ablation all imaging layer material in said exposed areas but sufficient to cause said exposed areas to interact with said porous hydrophilic surface and bond strongly thereto so as to provide a durable oleophilic image that is useful in lithographic printing;
Specification