Electrophotographic printing system including page rotations to reduce burn-in artifacts

1. A method for reducing image burn-in artifacts in an electrophotographic printing system, comprising:

receiving a print job including image data for a set of pages to be printed with the electrophotographic printing system;

determining that the image data for a sequence of pages in the print job are similar; and

using an electrophotographic print engine to print the similar pages using a pattern of page orientations including a first page orientation and a second page orientation, wherein the image data for the second page orientation is rotated 180 degrees relative to the image data for the first page orientation.

2. The method of claim 1 , wherein printing the similar pages using the pattern of page orientations includes:

a) printing the image data for N1 pages in the first orientation;

b) printing the image data for N2 pages in the second orientation, N1 and N2 being predefined integers;

c) repeating steps a)-b) until all of the similar pages have been printed.

3. The method of claim 2 , wherein N1 and N2 are integers between 50 and 200.

4. The method of claim 1 , wherein the image data for a sequence of pages are determined to be similar based on metadata associated with the print job indicating that the print job includes multiple copies of the same page having the same image data.

5. The method of claim 1 , wherein the image data for a sequence of pages are determined to be similar by automatically analyzing the image data to compute a predefined image similarity metric, and designating sequential pages to be similar by comparing the image similarity metric to a predefined threshold.

6. The method of claim 5 , wherein computing the image similarity metric includes:

computing a cross-track image profile from the image data for sequential pages;

computing image difference statistics from the cross-track image profiles; and

computing the image similarity metric responsive to the image difference statistics.

7. The method of claim 6 , wherein the image difference statistics include a mean absolute difference between the cross-track image profiles, an RMS difference between the cross-track image profiles, a standard deviation of the difference between the cross-track image profiles or a variance of the difference between the cross-track image profiles.

8. The method of claim 6 , further including computing a local range of the cross-track image profile as a function of cross-track position, and wherein the sequential pages are only designated to be similar if a maximum value of the local range of the cross-track image profile exceeds a predefined threshold, T R .

9. The method of claim 5 , wherein computing the image similarity metric includes:

computing cross-track image profiles {circumflex over (P)} 1 (x) from the image data I(x,y) for a set of sequential pages, where:

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i is the image number, x and y are the cross-track and in-track pixel positions, respectively, Ny is the number of rows in the image data, and p0 is the midpoint of the code value range for the image data;

determining an average cross-track profile B i (x) by averaging the cross-track image profiles for the set of K sequential pages using the equation, where:

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and K is the number of pages being averaged;

computing a local range of the average cross-track image profile in a window of cross-track positions as a function of cross-track position, where:

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the max(⋅) and min(⋅) functions return the maximum and minimum values, respectively, of the average cross-track profile in a window of cross-track positions x j given by (x−W/2)≤x j ≤(x+W/2);

computing the image similarity metric S i by determining a maximum of the local range of the average cross-track image profile, where

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and the max(⋅) function determines the maximum value across the range of x values.

10. The method of claim 5 , wherein computing the image similarity metric includes:

computing a difference image representing a difference between the image data for sequential pages;

computing image difference statistics from the difference image; and

computing the image similarity metric responsive to the image difference statistics.

11. The method of claim 10 , wherein the image difference statistics include a mean absolute difference of the difference image, an RMS difference of the difference image, a standard deviation of the difference image or a variance of the difference image.

12. The method of claim 1 , wherein the electrographic printing system includes a finishing system, and wherein the finishing system positions the pages printed in the first orientation in a first position and the pages printed in the second orientation in a second position.

13. The method of claim 12 , wherein the pages printed in the first and second orientations are deposited into a single output tray, and wherein the second position is offset laterally relative to the first position in the output tray.

14. The method of claim 12 , wherein the first position is a first output tray, and the second position is a second output tray.

15. The method of claim 1 , wherein the electrographic printing system includes a finishing system, and wherein the finishing system rotates the pages printed in one of the first and the second orientations so that they match the orientation of the pages printed in the other of the first and second orientations.

16. The method of claim 1 , further including applying a pattern of lateral translations to the similar pages wherein the image data is laterally translated such that it is printed at a different lateral position on the printed page.