Inspecting an imprinted substrate on a printing press
View Patent ↗A method of inspecting an imprinted substrate on a printing press comprises illuminating a portion of the substrate which has been imprinted with different colors at a plurality of printing units of the printing press. The method further comprises sensing light reflected by the substrate using a contact image sensor to produce data representative of the imprinted substrate, and comparing the data representative of the printed substrate with stored reference data.
1. A method of inspecting an imprinted substrate on a printing press, comprising:
illuminating a portion of the substrate which has been imprinted with different colors at a plurality of printing units of the printing press, each printing unit comprising a plate cylinder;
sensing light reflected by the substrate using a contact image sensor to produce data representative of the imprinted substrate;
comparing the data representative of the printed substrate with stored reference data.
2. The method of claim 1 , wherein the substrate is imprinted with a graphical/textual image.
3. The method of claim 1 , further comprising detecting color registration based on the comparing.
4. The method of claim 1 , wherein the substrate is a web.
5. The method of claim 1 , further comprising refracting the light reflected by the substrate with a continuous index of refraction.
6. The method of claim 1 , wherein the contact image sensor comprises a plurality of sensing elements, wherein a dimension of each sensing element is substantially equal to a dimension of a corresponding region of the substrate imaged by the sensing element.
7. The method of claim 1 , wherein the method inspects a newspaper substrate on a newspaper press.
8. The method of claim 1 , further comprising identifying a defect on the imprinted substrate based on the comparing.
9. The method of claim 2 , further comprising identifying an ink color error based on the comparing.
10. The method of claim 9 , further comprising generating ink key control signals based on the ink color error.
11. A method for inspecting an imprinted substrate on a printing press, comprising:
illuminating a portion of the substrate which has been imprinted with an image at a printing unit of the printing press, the printing unit comprising a plate cylinder;
sensing light reflected by the imprinted substrate with a plurality of sensing elements, wherein each sensing element senses light reflected by a corresponding region on the substrate to produce data representative of the corresponding region printed on the substrate, wherein a dimension of each sensing element is substantially equal to a dimension of the corresponding region printed on the substrate; and
comparing the data representative of the corresponding region printed on the substrate with stored reference data.
12. The method of claim 11 , wherein the dimensions of the sensing elements and corresponding regions is a width.
13. The method of claim 11 , wherein the sensed region of the substrate comprises a graphical/textual printed work.
14. The method of claim 11 , further comprising detecting color registration based on the comparing.
15. The method of claim 11 , wherein the sensed region of the substrate comprises color patches printed separate from other portions of a desired graphical/textual printed work, further comprising detecting an ink color error based on the comparing.
16. The method of claim 11 , wherein the substrate comprises a web.
17. The method of claim 11 , further comprising refracting light between the substrate and the sensing elements with a continuous index of refraction.
18. The method of claim 11 , wherein the method inspects a newspaper substrate on a newspaper press.
19. The method of claim 11 , wherein the substrate has been imprinted with different colors at a plurality of printing units of the printing press.
20. The method of claim 13 , further comprising identifying an ink color error based on the comparing and generating ink key control signals based on the ink color error.
21. The method of claim 13 , further comprising identifying a defect in the graphical/textual printed work based on the comparing.