Methods, apparatuses, and systems for detecting printing defects and contaminated components of a printer

Patent metadata

Field	Value
Publication number	US-12388937-B2
Application number	US-202418423105-A
Country	US
Kind code	B2
Filing date	Jan 25, 2024
Priority date	Jan 5, 2018
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

A method for printing defect detection includes processing and analyzing a difference image obtained by comparing an image scanned with a verifier to a reference image. The detected defects are grouped, and the grouping is refined. Confidence level values are then assigned to the refined groups, and analysis is performed to determine if one or more servicing actions should be taken.

First claim

The invention claimed is:

1. A method comprising:
capturing an image of printed content;
generating a difference image based on a comparison of the captured image of the printed content and a reference image, wherein the reference image correlates to the printed content; and
generating a plurality of rendered images based on applying a plurality of defect detection algorithms to the difference image, wherein each of the plurality of rendered images comprises one or more bright pixels that are assigned to at least one defect group from a plurality of defect groups.

2. The method of claim 1 , wherein the plurality of defect detection algorithms comprises one or more of a void detection algorithm, a wrinkle detection algorithm, or a banding and ink split detection algorithm.

3. The method of claim 1 , wherein each of the plurality of defect groups is associated with one of a plurality of defect types comprising void, wrinkle, banding and ink split.

4. The method of claim 3 , further comprising determining at least one defect type associated with the printed content from the plurality of defect types.

5. The method of claim 1 further comprising overlapping and analyzing the plurality of rendered images to determine whether at least one of the one or more bright pixels is common among two or more of the plurality of rendered images.

6. The method of claim 5 further comprising, in response to determine that the at least one of the one or more bright pixels is common among the two or more of the plurality of rendered images, performing additional processing of the plurality of rendered images.

7. The method of claim 6 , wherein performing the additional processing of the plurality of rendered images comprises overlapping the at least one of the one or more bright pixels that is common.

8. The method of claim 7 , wherein performing the additional processing of the plurality of rendered images comprises refining the one or more bright pixels assigned to the plurality of defect groups.

9. The method of claim 7 , wherein refining the one or more bright pixels assigned to the plurality of defect groups comprises reassigning one of the one or more bright pixels from one defect group to another defect group of the plurality of defect groups.

10. A printing system comprising:
a printer; and
a verifier communicatively coupled to the printer and comprising:
a processing unit;
a memory storing computer program code, the memory and the computer program code configured to, with the processing unit, cause the verifier to at least:
identify one or more groups of difference pixels;
refine the one or more identified groups of difference pixels into one or more defect types;
determine a confidence level for at least one of the one or more defect types; and
determine one or more defects based on the determined confidence level for at least one of the one or more defect types.

11. The printing system of claim 10 , wherein the memory and the computer program code are configured to, with the processing unit, cause the verifier to further create a group of difference points in response to determining that a difference point is within a predetermined distance of another difference point.

12. The printing system of claim 11 , wherein the memory and the computer program code are configured to, with the processing unit, cause the verifier to further detect a printhead contamination based on a count of difference pixels in respective groups of difference pixels.

13. The printing system of claim 11 , wherein the memory and the computer program code are configured to, with the processing unit, cause the verifier to further determine whether the group of difference points is collinear based on attempting to connect three difference points in the group of difference points on a straight line.

14. The printing system of claim 13 , wherein the memory and the computer program code are configured to, with the processing unit, cause the verifier to further determine that the one or more defects are caused by wrinkles on a ribbon in response to determining that at least one or more difference points are collinear.

15. The printing system of claim 13 , wherein the memory and the computer program code are configured to, with the processing unit, cause the verifier to further determine that the one or more defects are caused by a contaminated platen roller in response to determining that at least one or more difference points are non-collinear.

16. The printing system of claim 10 , wherein the memory and the computer program code are configured to, with the processing unit, cause the verifier to further refine the one or more identified groups of difference pixels by creating a separate difference image for each detected defect type of void, ribbon wrinkle, banding, and ink split.

17. The printing system of claim 10 , wherein the printer is configured to issue a notification reporting a defect.

18. The printing system of claim 10 , wherein the printer is configured to prescribe a recommended course of action corresponding to at least one or more identified defect types.

19. The printing system of claim 10 , wherein the one or more groups of difference pixels are identified using a reference image that is generated based on a print command string.

20. The printing system of claim 19 , wherein the one or more groups of difference pixels are identified by comparing the reference image with a printed image.

Assignees

• Hand Held Prod Inc

Inventors

• D'Armancourt Sebastien
• Celinder Thomas Axel Jonas
• Ackley H Sprague
• Aspenns Glenn David

Classifications

• H04N1/00082

  Adjusting or controlling (interrupting an operation H04N1/00915; inhibiting an operation H04N1/00925) · CPC title

• H04N1/00045

  using a reference pattern designed for the purpose, e.g. a test chart · CPC title

• H04N1/00039

  Analysis, i.e. separating and studying components of a greater whole · CPC title

• H04N1/00037

  Detecting, i.e. determining the occurrence of a predetermined state (H04N1/00031 takes precedence) · CPC title

• G06T7/0002

  Inspection of images, e.g. flaw detection · CPC title