Method and apparatus for thermal development with supporting surface for a development medium

Abstract

This invention relates to a method and apparatus for thermally developing a photosensitive element. The thermal development method includes heating the photosensitive element to a temperature sufficient to cause a portion of a composition layer in the element to liquefy, soften, or melt; supporting a development medium with a non-rotating surface to provide contact of the development medium with the heated photosensitive element; and providing relative movement between the development medium and the non-rotating surface.

1 . An apparatus for forming a relief pattern from a photosensitive element having an exterior surface and containing a composition layer capable of being partially liquefied comprising: 
 means for heating the exterior surface to a temperature sufficient to cause a portion of the layer to partially liquefy;    means for supporting a development medium to provide contact with the exterior surface adjacent the partially liquefied portion; and    means for providing relative movement between the development medium and the means for supporting;    wherein the means for supporting comprises a non-rotating surface opposite the partially liquefied portion.    
   
   
       2 . The apparatus of  claim 1  wherein the means for supporting comprises a non-cylindrical support member.  
   
   
       3 . The apparatus of  claim 1  wherein the means for supporting further comprises a support member having a cross-sectional shape selected from the group consisting of elliptical, arcuate, parabolic, circular, semi-circular, wedge, triangular, rectangular, and polygonal shapes.  
   
   
       4 . The apparatus of  claim 1  wherein the means for supporting further comprises a support member having a means for providing heat to the support member.  
   
   
       5 . The apparatus of  claim 1  wherein the non-rotating surface is selected from the group consisting of planar surfaces and arcuate surfaces.  
   
   
       6 . The apparatus of  claim 5  wherein the non-rotating surface is arcuate, and selected from the group consisting of convex surfaces and concave surfaces, wherein the concave surfaces conform to a portion of the exterior surface.  
   
   
       7 . The apparatus of  claim 1  wherein the non-rotating surface comprises a radius of curvature less than 40 millimeters.  
   
   
       8 . The apparatus of  claim 1  wherein the non-rotating surface comprises a radius of curvature between 8 and 15 millimeters.  
   
   
       9 . The apparatus of  claim 1  wherein the non-rotating surface comprises a projecting edge about which the development medium traverses.  
   
   
       10 . The apparatus of  claim 1  wherein the means for supporting comprises more than one non-rotating surface each having a radius of curvature, wherein each radius of curvature can be the same or different.  
   
   
       11 . The apparatus of  claim 1  wherein the means for supporting comprises a support member having more than one non-rotating surface, the apparatus further comprising means for indexing the support member to position each of the more than one non-rotating surface adjacent the exterior surface.  
   
   
       12 . The apparatus of  claim 1  wherein the means for supporting comprises a support member having a semi-circular cross-sectional shape and having a cylindrical surface portion coinciding with the non-rotating surface.  
   
   
       13 . The apparatus of  claim 12  wherein the means for supporting further comprises means for buttressing the support member.  
   
   
       14 . The apparatus of  claim 12  wherein the cylindrical surface portion has a radius of curvature less than 40 millimeters.  
   
   
       15 . The apparatus of  claim 1  wherein the means for supporting comprises a support member having a circular cross-sectional shape and having a cylindrical surface portion coinciding with the non-rotating surface.  
   
   
       16 . The apparatus of  claim 1  further comprising means for buttressing the support means opposite the non-rotating surface.  
   
   
       17 . The apparatus of  claim 1  further comprising means for supporting the photosensitive element; and 
 means for delivering the development medium to the exterior surface.    
   
   
       18 . The apparatus of  claim 1  further comprising means for moving the means for supporting.  
   
   
       19 . The apparatus of  claim 1  further comprising means for removing the development medium from the exterior surface.  
   
   
       20 . The apparatus of  claim 1  further comprising means for applying tension to the development medium.  
   
   
       21 . The apparatus of  claim 1  wherein the means for supporting further comprises means for pressing the photosensitive element and the development medium into contact at a pressure sufficient for at least a portion of the liquefied material of the composition layer to be absorbed by the development medium.  
   
   
       22 . The apparatus of  claim 1  wherein the photosensitive element is a photopolymerizable printing element.  
   
   
       23 . The apparatus of  claim 1  wherein the means for heating is selected from the group consisting of 
 a first heating means that applies heat to the exterior surface of the composition layer adjacent where the development medium contacts the layer, the first heating adapted to heat the exterior surface of the layer;    a second heating means to heat the means for supporting the development medium to a temperature capable of heating the exterior surface of the composition layer while the development medium is contacting the exterior surface of the layer;    a third heating means to heat the means for supporting the photosensitive element to a temperature capable of heating the exterior surface of the composition layer;    combination of the first heating means and the second heating means;    combination of the first heating means and the third heating means;    combination of the second heating means and the third heating means; and    combination of the first heating means, the second heating means, and the third heating means,    wherein the first heating means, the second heating means, and the third heating means, individually or in the above combinations, is capable of heating the exterior surface of the composition layer sufficiently to cause a portion of the layer to liquefy.    
   
   
       24 . A method for forming a relief pattern from a photosensitive element having an exterior surface and containing a composition layer capable of being partially liquefied comprising: 
 heating the exterior surface to a temperature sufficient to cause a portion of the layer to partially liquefy; and    supporting a development medium for contacting with the exterior surface adjacent the partially liquefied portion;    wherein the supporting step comprises contacting a non-rotating surface opposite the partially liquefied portion, and providing relative movement between the development medium and the non-rotating surface.    
   
   
       25 . The method of  claim 24  wherein the supporting step is with a non-cylindrical support member.  
   
   
       26 . The method of  claim 24  wherein the supporting step is with a support member having a cross-sectional shape selected from the group consisting of elliptical, parabolic, arcuate, circular, semi-circular, wedge, triangular, rectangular, and polygonal shapes.  
   
   
       27 . The method of  claim 24  wherein the non-rotating surface is selected from the group consisting of planar surfaces and arcuate surfaces.  
   
   
       28 . The method of  claim 27  wherein the non-rotating surface is arcuate, and selected from the group consisting of convex surfaces and concave surfaces, wherein the concave surfaces conform to a portion of the exterior surface.  
   
   
       29 . The method of  claim 24  wherein the non-rotating surface comprises a radius of curvature less than 40 millimeters.  
   
   
       30 . The method of  claim 24  wherein the non-rotating surface comprises a radius of curvature between 8 and 15 millimeters.  
   
   
       31 . The method of  claim 24  further comprising traversing the development medium on a projecting edge of the non-rotating surface.  
   
   
       32 . The method of  claim 24  wherein the supporting step comprises supporting the development medium with a support member having more than one non-rotating surface each having a radius of curvature, wherein each radius of curvature can be the same or different.  
   
   
       33 . The method of  claim 24  wherein the supporting step comprises supporting the development medium with a support member having more than one non-rotating surface, the method further comprising indexing the support member to position each of the more than one non-rotating surface adjacent the exterior surface.  
   
   
       34 . The method of  claim 24  wherein the supporting step comprises supporting the development medium with a support member that is semi-cylindrical having a cylindrical surface portion coinciding with the non-rotating surface.  
   
   
       35 . The method of  claim 34  wherein the cylindrical surface portion has a radius of curvature less than  40  millimeters.  
   
   
       36 . The method of  claim 24  further comprising buttressing the non-rotating surface.  
   
   
       37 . The method of  claim 24  further comprising 
 supporting the photosensitive element on a base member; and    delivering the development medium to the exterior surface.    
   
   
       38 . The method of  claim 24  further comprising moving a support member comprising the non-rotating surface.  
   
   
       39 . The method of  claim 24  further comprising removing the development medium from the exterior surface.  
   
   
       40 . The method of  claim 24  further comprising tensioning the development medium.  
   
   
       41 . The method of  claim 24  further comprising pressing the development medium and the photosensitive element into contact at a pressure sufficient for at least a portion of the liquefied material of the composition layer to be absorbed by the development medium.  
   
   
       42 . The method of  claim 24  wherein the photosensitive element is a photopolymerizable printing element.  
   
   
       43 . The method of  claim 24  wherein the heating step is selected from the group consisting of 
 a first heating applying heat to the exterior surface of the composition layer adjacent where the development medium contacts the layer, the first heating adapted to heat the exterior surface of the layer;    a second heating to heat the non-rotating surface to a temperature capable of heating the exterior surface of the composition layer while the development medium is contacting the exterior surface of the layer;    a third heating to heat a base member for the photosensitive element to a temperature capable of heating the exterior surface of the composition layer;    combination of the first heating and the second heating;    combination of the first heating and the third heating;    combination of the second heating and the third heating; and    combination of the first heating, the second heating, and the third heating,    wherein the first heating, the second heating, and the third heating, individually or in the above combinations, is capable of heating the exterior surface of the composition layer sufficiently to cause a portion of the layer to liquefy.    
   
   
       44 . The method of  claim 24  further comprising exposing the photosensitive element to actinic radiation.  
   
   
       45 . The method of  claim 44  wherein the exposing step is imagewise through an in-situ mask, through a phototool, or by a laser.  
   
   
       46 . A flexographic printing form made according to the method of  claim 44 .  
   
   
       47 . The apparatus of  claim 1  wherein the non-rotating surface is stationary.  
   
   
       48 . The apparatus of  claim 1  wherein the non-rotating surface moves less than one revolution about an axis.  
   
   
       49 . The method of  claim 24  wherein the non-rotating surface is stationary.  
   
   
       50 . The method of  claim 24  further comprising moving the non-rotating surface less than one revolution about an axis.