Inspecting an imprinted substrate on a printing press

• US 8,039,826 B2
• Filed: 04/22/2010
• Issued: 10/18/2011
• Est. Priority Date: 08/09/2004
• Status: Active Grant

• Current Assignee: Baldwin Americas Corporation (Forsyth Baldwin LLC)
• Original Assignee: Quad/Tech Incorporated
• Inventors: Hansen, Mark R., Pearson, Eric, Moersfelder, Bradly S., Seymour, John C., Noffke, Patrick James
• Primary Examiner(s): Legasse, Jr.; Francis M
• Application Number:
  US12/765,723
• Publication Number:
  US 20100264338A1
• Time in Patent Office: 544 Days
• Field of Search: 25055904-55907, 25055937-55944, 356/429, 356/430, 356/431, 358/474
• US Class Current: 250/559.39
• CPC Class Codes: B41F 33/0081 Devices for scanning register marks

Abstract

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.

Claims

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.