Set of color ink compositions for ink-jet printing and method of forming color images using the color ink set

摘要

A set of color ink compositions for ink-jet printing includes yellow, magenta and cyan ink composition, each of which having water, a water-soluble coloring agent, a wetting agent, a surfactant and an antiseptic and mildewproofing agent, and the yellow ink composition has the lightness index L* of 95+/-5 and the chromaticness indices a* and b* of respectively -6+/-5 and 23 +/-12, the magenta ink composition has the lightness index L* of 75+/-5 and the chromaticness indices a* and b* of respectively 55+/-25 and -28+/-10, and the cyan ink composition has the lightness index L* of 87+/-5 and the chromaticness indices a* and b* of respectively -35+/-10 and -19+/-8. Further, color ink images are formed on a recording material with a St+E,uml o+EE ckigt sizing degree of 10 sec or more using the above set of color ink compositions and a printing head with a plurality of ink-ejecting orifices by performing dot printing on the recording material by ejecting the ink compositions from the ink-ejecting orifices with the printing head scanned over the recording material a plurality of times.