Pigmented inks for ink jet printers

摘要

There is provided an aqueous ink jet ink composition suitable for use in continuous ink jet printers comprising: (a) a surface modified carbon black pigment; (b) at least one organic pigment; and (c) an aqueous carrier medium. The black aqueous pigment ink formulated in accordance with this composition provides a dried ink film whereof the resistivity is increased to a level whereby no printer failure or print defects are caused by electrical shorts when the printer has been out of use for a sufficient time to allow the ink to dry out in parts of the apparatus. The ink may also comprise at least one dispersant for the organic pigment.