Method and system for detecting defects during the fabrication of a printing cylinder

Abstract

The invention relates generally to the field of printing. More specifically, the invention relates to a method and system for automatically detecting defects in a printing cylinder during its fabrication process. The invention further relates to a process for fabricating a printing cylinder.

1 . A method for detecting defects on an engravable material, the material being the peripheral surface of a printing cylinder, the method comprises: 
 acquiring an image of an engravable material, wherein said material is the peripheral surface of a printing cylinder; and    performing a morphological analysis of said image thereby detecting defects on said engravable material.    
   
   
       2 . The method according to  claim 1 , wherein said engravable material comprises a metal.  
   
   
       3 . The method according to  claim 2 , wherein said metal comprises copper, aluminum, zinc or a combination thereof.  
   
   
       4 . The method according to  claim 1 , wherein said engravable material comprises a polymer.  
   
   
       5 . The method according to  claim 4 , wherein said polymer comprises rubber.  
   
   
       6 . The method according to  claim 2 , wherein said material is processed to increase the level of smoothness.  
   
   
       7 . The method according to  claim 1 , wherein said engravable material comprises a plurality of cells engraved on said engravable material according to a predetermined patterning scheme and wherein the image of said engravable material comprises the image of said cells.  
   
   
       8 . The method according to  claim 1 , wherein said engravable material further comprising a wear-proof layer.  
   
   
       9 . The method according to  claim 8 , wherein said wear-proof layer comprises metal.  
   
   
       10 . The method according to  claim 1 , wherein said engravable material comprises a pattern-generating layer.  
   
   
       11 . The method according to  claim 1 , wherein said engravable material comprises a transfer layer.  
   
   
       12 . The method according to  claim 7 , wherein the step of performing said morphological analysis comprises use of a predefined set of characteristics to identify defective cells and the position thereof.  
   
   
       13 . The method according to  claim 12 , wherein said predefined set of characteristics comprises: pattern regularity, dimensions of cells, shape of cells, cross-sectional area of cells, bridges between adjacent cells, distance between adjacent cells, depth of cells or any combination thereof.  
   
   
       14 . The method according to  claim 7 , wherein the step of performing the morphological analysis comprises the step of comparing said image to a reference image, wherein said reference image is obtained from said patterning scheme.  
   
   
       15 . The method according to  claim 10 , wherein the step of performing said morphological analysis comprises the step of detecting defects related to non-uniformity of the thickness and/or surface of said pattern-generating layer.  
   
   
       16 . Use of the method according to  claim 1  in a process for fabricating a printing cylinder.  
   
   
       17 . A system for detecting defects on an engravable material, the material being the peripheral surface of a printing cylinder, the system comprises: 
 a moveable image acquiring apparatus for outputting, at different stages of the fabrication process, data related to an image of an engravable material, wherein said material is the peripheral surface of a printing cylinder, the apparatus is capable of moving forwards and backwards along an imaginary line that is essentially parallel to the rotation axis of said cylinder;    a controllable mechanism, for rotating said cylinder and operating the image acquiring apparatus; and    a controller, functionally coupled to said controllable mechanism for causing it to rotate the cylinder and move said image acquiring apparatus in synchronization, wherein said controller is configured to receive the data related to said image and to output data related to the detection of defects on said engravable material.    
   
   
       18 . The system according to  claim 17 , wherein said engravable material comprises a metal.  
   
   
       19 . The system according to  claim 19 , wherein said metal comprises copper, aluminum, zinc or a combination thereof.  
   
   
       20 . The system according to  claim 17 , wherein said engravable material comprises a polymer.  
   
   
       21 . The system according to  claim 20 , wherein said polymer comprises rubber.  
   
   
       22 . The system according to  claim 18 , wherein said material is processed to increase the level of smoothness.  
   
   
       23 . The system according to  claim 17 , wherein said engravable material comprises a plurality of cells engraved on said material according to a predetermined patterning scheme and wherein the image of said engravable material comprises the image of said cells.  
   
   
       24 . The system according to  claim 17 , wherein said engravable material further comprising a wear-proof layer.  
   
   
       25 . The system according to  claim 24 , wherein said wear-proof layer comprises a metal.  
   
   
       26 . The system according to  claim 17 , wherein said engravable material comprises a pattern-generating layer.  
   
   
       27 . The system according to  claim 17 , wherein said engravable material comprises a transfer layer.  
   
   
       28 . The system according to  claim 23 , wherein said controller uses a predefined set of characteristics to identify defective cells and the position thereof.  
   
   
       29 . The system according to  claim 28 , wherein said predefined set of characteristics comprises: pattern regularity, dimensions of cells, shape of cells, cross-sectional area of cells, bridges between adjacent cells, distance between adjacent cells, depth of cells or any combination thereof.  
   
   
       30 . The system according to  claim 23 , wherein said controller is configured to locate the position of the defective cells on said engravable material by comparing data representative of said image of said engravable material to data representative of a reference image, wherein said reference image is obtained from said patterning scheme.  
   
   
       31 . The system according to  claim 26 , wherein said controller is configured to detect defects related to non-uniformity of the thickness and/or surface of said pattern-generating layer.  
   
   
       32 . The system according to  claim 17 , further comprising a GUI to display a picture of said defects.  
   
   
       33 . The system according to  claim 32 , wherein said GUI further provides processed data related to said defects.  
   
   
       34 . The system according to  claim 33 , wherein said processed data related to said defects comprises a list of said defects, size of said defects, distribution of said sizes of said defects, shapes of said defects, the influence of said defects on the quality of the printing picture or any combination thereof.  
   
   
       35 . A printing cylinder fabrication process designed to enable the detection of defects on an engravable material, the material being the peripheral surface of a printing cylinder, the process comprises: 
 acquiring an image of an engravable material, wherein said material is the peripheral surface of a printing cylinder; and    performing a morphological analysis of said image thereby detecting defects on said engravable material.    
   
   
       36 . The process according to  claim 35 , wherein said engravable material comprises a metal.  
   
   
       37 . The process according to  claim 36 , wherein said metal comprises copper, aluminum, zinc or a combination thereof.  
   
   
       38 . The process according to  claim 35 , wherein said engravable material comprises a polymer.  
   
   
       39 . The process according to  claim 38 , wherein said polymer comprises rubber.  
   
   
       40 . The process according to  claim 36 , wherein said material is processed to increase the level of smoothness.  
   
   
       41 . The process according to  claim 35 , wherein said engravable material comprises a plurality of cells engraved on said material according to a predetermined patterning scheme and wherein the image of said engravable material comprises the image of said cells.  
   
   
       42 . The process according to  claim 35 , wherein said engravable material further comprising a wear-proof layer.  
   
   
       43 . The process according to  claim 42 , wherein said wear-proof layer comprises a metal.  
   
   
       44 . The process according to  claim 35 , wherein said engravable material comprises a pattern-generating layer.  
   
   
       45 . The process according to  claim 35 , wherein said engravable material comprises a transfer layer.  
   
   
       46 . The process according to  claim 41 , wherein the step of performing said morphological analysis comprises use of a predefined set of characteristics to identify defective cells and the position thereof.  
   
   
       47 . The process according to  claim 46 , wherein said predefined set of characteristics comprises: pattern regularity, dimensions of cells, shape of cells, cross-sectional area of cells, bridges between adjacent cells, distance between adjacent cells, depth of cells or any combination thereof.  
   
   
       48 . The process according to  claim 41 , wherein the step of performing said morphological analysis comprises the step of comparing said image to a reference image, wherein said reference image is obtained from said patterning scheme, thereby locating the position of defective cells on said engravable material.  
   
   
       49 . The process according to  claim 44 , wherein the step of performing the morphological analysis comprises the step detecting defects related to non-uniformity of the thickness and/or surface of said pattern-generating layer.