Economical method & apparatus for objectively fixing error thresholds and checking color accuracy

A remote-proofing method for use in a proofing station and comprising automatically:

• printing a color calibration pattern with the printer;
• measuring calibration-pattern colors with a measuring device;
• based on the measurements, deciding whether color is acceptable;
• if a result of the deciding step is negative, then performing a color-correction procedure;
• and wherein
• the printing step comprises printing a reduced subset of colors from a different color calibration pattern used automatically by the same printer for the color-correction procedure.

A printer with automatic color checking;

• said printer comprising:
• a scanning inkjet print engine forming an image hardcopy on a printing medium;
• an image-data input;
• means for rendering data from the input to actuate the engine and form the image hardcopy, with first print parameters;
• means for printing a color calibration pattern in a margin of the medium, with the image, but with second print parameters;
• a sensor mounted in the engine for scanning to measure calibration-pattern colors;
• an analog-to-digital converter operating on measurement signals from the sensor to derive digital measurement values;
• means for determining, based on the measurement values, whether color in the image hardcopy is acceptable;
• and
• means, responsive to preliminary measurement signals from the sensor, for setting offset and gain in the converter;
• and
• a memory holding statistically derived calibration threshold values for comparison with the measurement values by the determining means.