Printing systems and methods for operating printing systems

摘要

Methods performed by a printing system are described herein. A portion of a print area is located by operating an optical sensor to respond to a color shift. The color shift is from a printed reference color. The color shift is caused by a fixer fluid applied to the portion. Printing systems and tangible machine readable storage mediums are also described herein.

主权项

1. A method of operating a printing system, the method comprising:
locating at least one portion of a print area by operating an optical sensor of the printing system to respond to a color shift from a printed reference color, the color shift being caused by a fixer fluid applied to the at least one portion, wherein the reference color is predetermined for improving the response of the optical sensor to the color shift, and from a plurality of printed colors by:
obtaining a plurality of emission spectra for the plurality of printed colors, the plurality of emission spectra including, for each of the printed colors, a first emission spectrum obtained from the color without being treated with the fixer fluid and a second emission spectrum obtained from the color treated with the fixer fluid;determining, for each of the printed colors, emission differences between the first emission spectrum and the second emission spectrum at different frequencies, the emission differences resulting from treatment of the color with the fixer fluid; andpredetermining the reference color from the plurality of printed colors according to the determined emission differences.