Sampling of customer images as color data for process control
View Patent ↗A controls system and method of print quality control for a printing system. The controls system uses printed output images as a continuous source of data for control processes. An image quality detector is positioned to detect color data in a printed image after the image is fused to a copy sheet. The present invention samples a wide range of colors in the image in order to calibrate a process station and ensure accurate production of color and/or other image quality parameters. The image quality detector examines an output image and compares the appearance of output image to a desired appearance. When an error exists, the printing system adjusts a process station to correct for variations and inconsistencies in a printed image. The detector of the present invention moves to different locations as the image exits from the printing system to sample a range of image quality parameters in the image.
1. A method of calibrating a printing system suitable for forming an output image representative of an input image, the method comprising:
forming and printing an output image on a support sheet;
detecting an image quality parameter within a predetermined area of the output image;
comparing the image quality parameter with an input parameter to determine an error adjustment;
adjusting the image quality parameter based on the error adjustment; and
automatically controlling a process station in the printing system as a function of the image quality parameter determined in the detecting step and adjusted in the adjusting step.
2. The method of claim 1 , wherein the image quality parameter comprises the color coordinates of the output image.
3. The method of claim 2 , wherein the color coordinates in the output image are detected using a spectrophotometer.
4. The method of claim 3 , wherein the spectrophotometer senses a range of color coordinates in the output image.
5. The method of claim 1 , wherein the process station comprises a look-up table for determining a color toner formula.
6. The method of claim 5 , wherein the step of controlling includes modifying an entry of the look-up table.
7. The method of claim 1 , wherein the step of forming an output image further comprises selecting a predetermined area to be detected.
8. The method of claim 7 , further comprising a step of moving a sensor to the predetermined area of the output image.
9. The method of claim 1 , wherein the input parameter is a proportion of constituent color spectra, and the error adjustment affects the proportion of the spectra of the image quality parameter.
10. A process control system for calibrating a printing system, comprising:
an image forming system for forming a developed image based on an input quality parameter;
a support sheet for receiving the developed image to form an output image representative of an output image;
an image quality sensor for measuring an output quality parameter of the output image on the support sheet and generating a signal representative of the image quality parameter in response to a comparison between the output quality parameter and the input quality parameter.
11. The system of claim 10 , further comprising an image controller for calibrating a process station as a function of the signal generated by the image quality sensor, the image controller adjusting the image forming system based on the comparison.
12. The system of claim 11 , wherein the sensor comprises a spectrophotometer for measuring color coordinates in the output image.
13. The system of claim 12 , wherein the process station comprises a look-up table for determining a color toner formula.
14. The system of claim 13 , wherein the controller modifies an entry of the look-up table to comprise a new color toner formula.
15. The system of claim 11 , wherein the sensor is movable along a predetermined path.
16. The system of claim 15 , wherein the image controller directs the sensor to a plurality of positions along the predetermined path so as to measure a range of image quality parameters.
17. A process control system for calibrating a printing system suitable for forming an output image representative of an input image, comprising:
a movable image quality sensor for measuring an output image quality parameter in an image and generating a signal representative of the output image quality parameter in response to a comparison between the output image quality parameter and an input image quality parameter.
18. The process control system of claim 17 , further comprising an image processor for decomposing an input image and producing output data for rendering an output image by a print engine.
19. The process control system of claim 18 , wherein the image processor controls the movement of the sensor.
20. The system of claim 19 , wherein the image processor moves the sensor along a predetermined path so as to determine a range of color coordinates in the output image.