US Patent 8126199 Identification of faulty jets via sensing on customer images

Systems and methods monitor jets in a color imaging device to identify and correct faulty jets without interrupting a print job. The relationship between the output of the imaging device and the sensor values of a sensor is characterized in a correspondence table. Thereafter, an image produced by the imaging device is measured by the sensor at multiple locations for a group of jets including jets each corresponding a different color of the imaging device color space. The measured output at each of the multiple locations is compared with two or more sets of predicted sensor outputs generated from the color coordinates used to produce the image at the corresponding location and the correspondence table, the set of predicted sensor outputs including at least one predicted sensor output generated with at least one jet set as faulty. At least one jet is determined as operating properly or being faulty based on a comparison of the sets of predicted sensor outputs and the corresponding measured outputs for the multiple locations.