Claims
- 1. A printer-checking method comprising automatically:
printing a color calibration pattern; with a particular sensor, measuring calibration-pattern colors; comparing the measurements with product-line data; for substantially each measurement, deriving a statistic pair comprising a product-line statistic and a particular-sensor statistic; from each statistic pair, computing an overall statistic; and based on the overall statistic, deciding whether color is acceptable.
- 2. The method of claim 1, wherein:
the printing, measuring, computing and deciding steps are performed automatically by the printer in a field environment.
- 3. The method of claim 2, wherein:
at least the deriving step is performed in laboratory design work for a product line prior to manufacture of the printer.
- 4. The method of claim 3, wherein:
the deriving step is coordinated with establishment of design goals for the product line in such a way that substantially all actually accepted color results are within the product-line color-accuracy design goals.
- 5. The method of claim 4, wherein:
a result of the deciding step is transmitted by the printer, at a first printer station, to another printer station for confirmation or evaluation.
- 6. The method of claim 2, further comprising the step of:
if a result of the deciding step is negative, then performing a color-correction procedure before relying on a printout made by the printer.
- 7. The method of claim 4, 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.
- 8. The method of claim 5, wherein the measuring step further comprises:
reading unprinted bare printing medium adjacent to the calibration pattern to compute the distance from printing elements to the printing medium at the pattern; and using the computed distance to adjust color measurements.
- 9. The method of claim 1, wherein the measuring step further comprises:
reading unprinted bare printing medium adjacent to the calibration pattern to compute the distance from printing elements to the printing medium at the target; and using the computed distance to adjust color measurements.
- 10. 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.
- 11. The method of claim 10, wherein:
a result of the deciding step is transmitted by the printer to another remote-proofing station for confirmation or evaluation.
- 12. The method of claim 11, further comprising the step of:
if a result of the deciding step is negative, then performing a color-correction procedure before relying on a proof made by the printer.
- 13. The method of claim 10, wherein the measuring step comprises:
preliminary measurement of at least a black ramp in the test pattern; and self calibration of the measuring device based upon the preliminary measurement.
- 14. The method of claim 13, wherein:
the measuring step further comprises preliminary measurement of saturated patches of primary colors; and the self calibration comprises adjustment of gain and offset for the measuring device, based upon the black and saturated-color preliminary measurements.
- 15. The method of claim 10, wherein:
the printing step comprises concatenating the color-calibration pattern with a production image to be printed, and printing both the pattern and image together as a single print job.
- 16. The method of claim 15, wherein:
the printing step comprises printing the calibration pattern in the margin of the production image.
- 17. The method of claim 16, wherein:
the printing step further comprises printing a fiducial mark with the calibration pattern, and the measuring step comprises locating the calibration pattern by the fiducial mark.
- 18. The method of claim 17, wherein:
the measuring step comprises scanning white space adjacent to the calibration pattern to enable compensation for variation in distance between image-forming elements and the printing medium.
- 19. 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.
- 20. The device of claim 17, further comprising:
means for scanning the sensor over the printing medium near the calibration pattern, to acquire data used in compensating for variation of spacing between printing elements and printing medium, near an edge of the medium.
- 21. The device of claim 17, wherein:
the threshold values are statistically derived in laboratory design prior to manufacture of the print engine.
- 22. The device of claim 17, wherein:
the first print parameters comprise use of composite colors and application of a color profile; and the second print parameters comprise substantially pure primary colorants and substantial absence of any color profile.
RELATED PATENT DOCUMENTS
[0001] Related documents include other, coowned U.S. utility-patent documents hereby incorporated by reference in their entirety into this document. They are in the names of Francesc Subirada et al., Ser. Nos. 09/919,207 and 09/034,722, later issued as U.S. Pat. Nos. 6,___,___ and 6,___,___ respectively; Pau Soler et al., application Ser. No. 09/919,260, issued as U.S. Pat. No. 6,___,___; Thomas Baker et al., Ser. No. 09/183,819, issued as U.S. Pat. No. 6,___,___; Antoni Gil Miquel, Ser. No. 09/642,417, later issued as U.S. Pat. No. 6,___,___; Vilanova et al., Ser. No. 09/945,492, issued as U.S. Pat. No. 6,___,___; Jodra et al., Ser. No. 09/832,638, issued as U.S. Ser. No. 6,___,___; Jodra et al., attorney's docket code 60011837Z154, later assigned Ser. No. 10/___,___ and issued as 6,___,___; Boleda et al., Ser. No. 09/942,070, issued as 6,___,___; and others cited therein.