RELOAD ERROR COMPENSATION IN COLOR PROCESS CONTROL METHODS

• US 20040240902A1
• Filed: 05/29/2003
• Published: 12/02/2004
• Est. Priority Date: 05/29/2003
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Dalal, Edul N., Crean, Peter A., Rasmussen, D. Rene
• Granted Patent: US 6,842,590 B2
• Time in Patent Office: Days
• US Class Current: 399/49
• CPC Class Codes: G03G 15/5041 Detecting a toner image, e.g. density, toner coverage, using a test patch G03G15/553 takes precedence
• CPC Class Codes: G03G 2215/00042 Optical detection
• CPC Class Codes: G03G 2215/0158 Colour registration

Abstract

A toner process control process, which includes substantially predicting an effect of reload error on a developed test patch, generating a developed test patch, sensing color density data from the test patch with a sensor, altering the sensed color density data to compensate for the predicted effect of reload error, and adjusting toner output according to the altered sensed color density data.

Claims

1. A toner control process, comprising:

substantially predicting an effect of reload error on a developed test patch;

generating a developed test patch;

sensing color density data from the test patch with a sensor;

altering the sensed color density data to compensate for the predicted effect of reload error;

adjusting toner output according to the altered sensed color density data.

2. The process of claim 1, wherein substantially predicting the effect of reload error on a developed test patch includes predicting a contribution to reload error based upon an initial color density of the at least one pixel of a digital image corresponding to the developed test patch.

3. The process of claim 2, wherein predicting a contribution to reload error based upon an initial color density of the at least one pixel of the digital image includes

determining a general relationship between the magnitude of reload error on a developed pixel and the color density of that pixel for a printing device;

receiving the color density of the at least one pixel of the digital image;

using the determined relationship between magnitude of reload error on a developed pixel and the color density of that pixel to predicting the contribution to reload error based upon the received color density of the at least one pixel of the digital image corresponding to the developed test patch.

4. The process of claim 1, wherein substantially predicting an effect of reload error for a developed test patch includes determining a contribution to reload error based upon the color densities of N previous pixels.

5. The process of claim 4, wherein each previous pixel is separated in a slow-scan direction by a distance corresponding to the circumference of a roll donating toner to develop the image and is located at substantially the same point in a fast-scan direction.

6. The process of claim 4, wherein determining a contribution to reload error based upon the color densities of the N previous pixels includes

determining a general relationship between the magnitude of reload error on a pixel and the color densities of N previous pixels for a printing device;

receiving the color densities of the N previous pixels printed;

using the determined relationship between magnitude of reload error on a pixel and the color densities of N previous pixels to predict the contribution to reload error based upon the received color densities of the previous N pixels printed.

7. The process of claim 4, further comprising combining N damping factors with the color densities of the N previous pixels.

8. The process of claim 4, wherein the contribution to reload error based upon the color densities of the N previous pixels is determined at a pixel resolution of not more than 50 dpi.

9. The process of claim 1, wherein substantially predicting how reload error will affect a developed image includes determining a weight factor.

10. A method for improving toner control processes, comprising:

generating a developed test patch;

determining an average density factor based upon a color density of at least one previously printed pixel,

wherein the average density factor includes a contribution based on an average imaging history contribution to each pixel of the test patch;

determining a weight factor corresponding to a toner color used to develop the test patch;

sensing color density data from the test patch with a sensor;

altering the sensed color density data to compensate for the average density factor and the weight factor;

adjusting toner output according to the altered sensed color density data.

11. A method for improving toner control processes, comprising:

substantially predicting an average effect of reload error over an area of a developed test patch;

generating a developed test patch;

sensing data from the test patch with a sensor;

uniformly altering the sensed data to compensate for the predicted average effect of reload error over the area;

adjusting toner output according to the altered sensed data.

12. The method of claim 11, wherein the area over which the effect of reload error is predicted is the entire area of the test patch.

13. The method of claim 11, wherein substantially predicting the average effect of reload error over an area of a developed rest patch involves

determining a plurality of contributions to the effect of reload error, each contribution corresponding to one of a plurality of pixels,

wherein each of the plurality of contributions includes the color densities of N previous pixels,

averaging the plurality of contributions, and

using the average of the plurality of contributions to predict the average effect of reload error.

14. The method of claim 13, wherein each previous pixel is separated in a slow-scan direction by a distance corresponding to the circumference of a roll donating toner to develop the image and is located at substantially the same point in a fast-scan direction.

15. The method of claim 13, wherein the N previous pixels of each of the plurality of contributions to the effect of reload error have a pixel resolution of not more than 50 dpi.

16. The method of claim 11, further comprising:

determining an average color density over an area of the developed test patch based upon the altered sensed data from the developed test patch,

determining how much to adjust toner levels based upon the average color density of the altered sensed data.

17. The process-method of claim 11, wherein substantially predicting how reload error will affect a developed image includes determining a weight factor.

18. A method for improving toner control processes, comprising:

determining a first density factor based upon a color density of at least one pixel of a digital image;

determining a second density factor based upon a color density of at least one previously printed pixel;

determining a weight factor;

generating a developed test parch;

sensing color density data from the test patch with a sensor;

altering the sensed data based upon the first density factor, the second density factor and the weight factor;

adjusting toner output according to the altered sensed data from the test patch.