Techniques for aligning images using page characteristics and image shifting

• US 20020181021A1
• Filed: 05/30/2001
• Published: 12/05/2002
• Est. Priority Date: 05/30/2001
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Stephens, Vance M.
• Granted Patent: US 7,456,995 B2
• Time in Patent Office: Days
• US Class Current: 358/1.18
• CPC Class Codes: B41J 11/0065 Means for printing without leaving a margin on at least one edge of the copy material, e.g. edge-to-edge printing
• CPC Class Codes: B41J 3/60 for printing on both faces of the printing material
• CPC Class Codes: H04N 1/00681 Detecting the presence, position or size of a sheet or correcting its position before scanning H04N1/047 takes precedence; mode signalling H04N1/333; skew detection or correction in image signals H04N1/3878
• CPC Class Codes: H04N 1/0071 Width
• CPC Class Codes: H04N 1/00713 Length
• CPC Class Codes: H04N 1/00734 Optical detectors
• CPC Class Codes: H04N 1/00785 Correcting the position of a sheet before scanning

Abstract

Techniques for printing an image on a print medium. Information regarding the actual size of the medium, or the actual placement of the medium at a print zone, is used to shift the image to properly align the image on the medium. The image can be shifted digitally, or by movement of the medium relative to the printing element.

Claims

1. A method for printing an image on a print medium, comprising:

positioning the print medium at a print zone;

determining actual medium size and/or medium placement characteristics;

using the size and/or placement characteristics, shifting an image to be printed relative to nominal size and/or medium placement characteristics; and

printing the shifted image on the medium.

2. The method of claim 1 wherein the image extends from lateral edge to lateral edge of the medium.

3. The method of claim 1 wherein said actual medium size and/or placement characteristics include an absolute location of a point on a leading edge of the medium.

4. The method of claim 1 wherein said actual medium size and/or placement characteristics include a skew characteristic of a leading edge of the medium.

5. The method of claim 1 wherein said actual medium size and/or placement characteristics include a medium length characteristic.

6. The method of claim 1 wherein said actual medium size and/or placement characteristics include a medium width characteristic.

7. The method of claim 1 wherein said shifting said image includes digitally shifting the image in a direction aligned with or transverse to a medium advance axis.

8. The method of claim 1 wherein said shifting said image includes digitally rotating the image.

9. The method of claim 1 wherein said shifting said image includes shifting the position of the print medium along a media feed path.

10. The method of claim 1 wherein an area of the image is smaller than an area of the medium, so that margins are provided on the medium after said printing.

11. A method for duplex printing an image on a print medium, comprising:

positioning a front side of the print medium at a print zone;

determining actual size and/or placement characteristics of the medium;

printing a front side image on said front side;

passing the print medium through a duplexing path to flip the print medium and present the back side of the print medium at the print zone for printing a back side image;

measuring leading edge and absolute location characteristics of the flipped print medium;

calculate shift parameters to shift the back side image to align with the front side image placement;

print a shifted back side image.

12. The method of claim 11 wherein the front and back side images extend from lateral edge to lateral edge of the medium.

13. The method of claim 11 wherein said actual medium size and/or placement characteristics include an absolute location of a point on a leading edge of the medium.

14. The method of claim 11 wherein said actual medium size and/or placement characteristics include a skew characteristic of a leading edge of the medium.

15. The method of claim 11 wherein said actual medium size and/or placement characteristics include a medium length characteristic.

16. The method of claim 11 wherein said actual medium size and/or placement characteristics include a medium width characteristic.

17. The method of claim 11 wherein said shifting said back side image includes digitally shifting the image in a direction aligned with or transverse to a medium advance axis.

18. The method of claim 11 wherein said shifting said back side image includes digitally rotating the image.

19. The method of claim 11 wherein said shifting said back side image includes shifting the position of the print medium along a media feed path.

20. The method of claim 11 wherein an area of the front side image is smaller than an area of the medium, and an area of the back side image is smaller than said area, so that margins are provided on the medium after said printing of said front side image and said back side image.