System and method employing secondary back exposure of flexographic plate

Abstract

A system for forming a relief image on a flexographic print plate comprises a laminator configured to laminate an imaged mask having a mask image to a front surface of a flexographic printing plate precursor. The mask image has mask image areas, each having a highlight value. The system also includes a main exposure unit configured to expose the flexographic printing plate precursor to curing radiation through the imaged mask, and a secondary exposure unit configured to expose selected areas of the flexographic printing plate precursor to curing radiation via a back surface of the flexographic printing plate precursor based on highlight values of corresponding mask image areas of the mask image.

1 . A system for forming a relief image on a flexographic print plate comprising:
 a laminator configured to laminate an imaged mask comprising a mask image, to a front surface of a flexographic printing plate precursor, the mask image comprising mask image areas, each mask image area having a highlight value;   a main exposure unit configured to expose the flexographic printing plate precursor to curing radiation through the imaged mask; and   a secondary exposure unit configured to expose selected areas of the flexographic printing plate precursor to curing radiation via a back surface of the flexographic printing plate precursor based on highlight values of corresponding mask image areas of the mask image.   
     
     
         2 . The system of  claim 1  wherein the selected areas comprise mask image areas having a highlight value at or below a highlight value threshold. 
     
     
         3 . The system of  claim 1  wherein the flexographic printing plate precursor comprises a substantially uniformly exposed layer proximate to the back surface formed by exposing the entire back surface to a curing radiation. 
     
     
         4 . The system of  claim 1  wherein the secondary exposure unit is indexed to the mask image based on stored digital data representative of the mask image. 
     
     
         5 . The system of  claim 1  wherein the secondary exposure unit comprises a plurality of individually controllable radiation sources. 
     
     
         6 . The system of  claim 5  wherein the individually controllable radiation sources comprise an array of ultraviolet light emitting diodes. 
     
     
         7 . The system of  claim 5  wherein the individually controllable radiation sources comprise a plurality of optical fibers coupled to individually addressable light sources. 
     
     
         8 . The system of  claim 5  wherein the individually controllable radiation sources comprise individually controllable micro mirrors of a digital light projector (DLP). 
     
     
         9 . The system of  claim 1  wherein the laminator comprises a rotating imaging drum, and the system further comprises a contact idler roller and a transport bed.