Preparation of gravure and intaglio printing elements using direct thermally imageable media

Abstract

A gravure printing element is fabricated using a negative-working thermally-imageable coating that is exposed using commercially available diode lasers, the coating being insensitive to ultraviolet light, daylight or visible light, and developable using aqueous media. A gravure etch mask is formed on a printing precursor by applying a coating of thermally-imageable material, curing the coating, imagewise illuminating the cured coating with a laser and removing with a developer the areas of the coating that were not illuminated. The masked precursor is then chemically etched to produce a gravure printing element.

1 . An apparatus for forming a gravure etch mask on a gravure printing precursor comprising: 
 (a) an apparatus for applying to a gravure printing precursor a coating of thermally-imageable material;    (b) an apparatus for curing said coating;    (c) a laser for imagewise illuminating said coating; and    (d) an apparatus for removing with a developer those areas of said coating that have not been illuminated.    
     
     
         2 . An apparatus according to  claim 1  wherein the apparatus for applying a coating comprises a sprayer or a roller.  
     
     
         3 . An apparatus according to  claim 1  wherein the coating is applied to a thickness of 0.5-15 microns.  
     
     
         4 . An apparatus according to  claim 1  wherein the coating is applied to a thickness of 0.7-10 microns.  
     
     
         5 . An apparatus according to  claim 1  wherein the apparatus for curing the coating uses heat to dry the coating.  
     
     
         6 . An apparatus accordingly to  claim 1  wherein the apparatus for curing the coating applies ultraviolet or infrared radiation to the coating.  
     
     
         7 . An apparatus according to  claim 1  wherein the laser emits light having a wavelength greater than 700 nm.  
     
     
         8 . An apparatus according to  claim 1  wherein the laser emits light having a wavelength between 700-1100 nm.  
     
     
         9 . An apparatus according to  claim 1  wherein the developer is an aqueous medium.  
     
     
         10 . An apparatus according to  claim 1  wherein the thermally-imageable material comprises: 
 (a) hydrophobic polymer particles; and    (b) a material for converting light into heat.    
     
     
         11 . An apparatus according to  claim 10  wherein the thermally-imageable material further comprises an organic base.  
     
     
         12 . An apparatus according to  claim 11  wherein the organic base comprises piperazine, 2-methylpiperazine and 4-dimenthylaminobenzaldehyde.  
     
     
         13 . An apparatus according to  claim 10  wherein the thermally-imageable material further comprises a metal complex.  
     
     
         14 . An apparatus according to  claim 13  wherein the metal-complex comprises zinc acetate, copper (11) phthalocyaninetetrasulphonic acid, tetra sodium salt, aluminum acetylacetonate, cobalt acetylacetonate, and zinc acetylacetonate.  
     
     
         15 . An apparatus according to  claim 10  wherein the thermally-imageable material further comprises an inorganic salt.  
     
     
         16 . An apparatus according to  claim 15  wherein the inorganic salt comprises sodium acetate, potassium carbonate, lithium acetate or sodium metasilicate.  
     
     
         17 . An apparatus according to  claim 10  wherein the thermally-imageable material further comprises an organic acid.  
     
     
         18 . An apparatus according to  claim 17  wherein the organic acid comprises malonic acid, D, L lactic acid or citric acid.