An inkjet ink is provided that has a greater
organic content than prior art inks. However, it is not simply enough to increase the
organic content; other factors must be considered as well. These include controlling
viscosity and
surface tension, as well as maintaining acceptable drytime. An inkjet ink composition that evidences reduced
outgassing and reduces paper cockle and curl comprises about 25 to 50 wt % of one or more organic co-solvents, has a
viscosity of 10 cp or less, and has a
surface tension of 40
dyne / cm or less. Advantageously, using a higher
solvent ink reduces cockle and curl. Cockle and curl are also reduced as the
water content of the ink is reduced. The present invention uses the higher
solvent inks in combination with underprinting. In underprinting, a fixer solution is first "printed" on the print medium, followed by printing the inkjet ink thereon. There is a synergism to this combination. Together, weaknesses of both approaches are addressed. The advantages are a longer life pen, due to the reduction of
outgassing of the ink, and reduced cockle and curl.