Patent ID: 7955426

Claim:
An ink set comprising at least the following pigment inks for an ink jet printer and different in color: a yellow ink, a magenta ink and a cyan ink, wherein the pigment inks each have a sedimentation rate, as indicated by equation (I), of 15% or less, and differences in the sedimentation rate between the pigment inks different in color are 4% or less: Sedimentation rate (%)=( S 0 −S 1 )/ S 0 ×100 (I) wherein S 0 represents an “initial ink concentration”, which is an absorbance at a wavelength of λmax (or at 500 nm when λmax is not detected) at the time when UV spectral characteristics are measured for a 1000-fold diluted solution of the ink; and S 1 represents an “ink concentration after sedimentation”, which is an absorbance at a wavelength of λmax (or at 500 nm when λmax is not detected) at the time when UV spectral characteristics are measured for a 1000-fold diluted solution of a supernatant obtained by centrifuging the ink at 16500 G at 1.60×10 7 g·sec, and wherein the ink set provides, when used for printing at a resolution of 1440 dpi, at the ink ratios (a) to (j) shown below, and at 70% duty for (a) to (g) and at an intermediate density of 50% duty for (h) to (j), print images of patch patterns having an average 20° glossiness (G 20 ) of all the patches of 35 or greater (a) Yellow 100% (b) Magenta 100% (c) Cyan 100% (d) Black 100% (e) Yellow 50%, magenta 50% (f) Yellow 50%, cyan 50% (g) Cyan 50%, magenta 50% (h) Yellow 30%, magenta 40%, cyan 30% (i) Yellow 30%, magenta 30%, cyan 30% (j) Yellow 40%, magenta 40%, cyan 20%.