an ink composition is provided for an ink - jet printer , preferably a thermal ink - jet printer . the composition comprises about 5 to 40 wt % glycol , about 60 to 90 wt % water , about 0 . 001 to 10 wt % polymer blend and about 1 to 7 wt % dye . the polymer blend includes both uncharged and charged monomeric units . the glycol and polymer blend act to form a soft plug that forms in the orifice of the ink - jet pen . the soft plug prevents further evaporaion of water , but unlike a hard plug , is readily blown out upon firing . the charged units in the polymer blend contribute to water fastness and light fastness of the dye on paper . further , by employing appropriate functional groups in the polymer blend , chemical degradation of the ink dye can be retarded on acid or alkaline papers .