Abstract: A color ink-jet printer is provided, with one pen for dispensing black ink onto a print medium and at least one pen for dispensing color ink onto a print medium. The pen for dispensing black ink is adapted to jet droplets of black ink of a first volume and the pen(s) for dispensing color ink are adapted to jet droplets of color ink of a second volume, with the first volume being larger than the second volume. Such a color ink-jet printer provides both superior text quality of the black ink and does not require as much ink volume of the color ink(s) as previous ink-jet printers.

Abstract: A color ink-jet printer is provided, with one pen for dispensing black ink onto a print medium and at least one pen for dispensing color ink onto a print medium. The pen for dispensing black ink contains a pigment-based ink and the pen(s) for dispensing color ink contain a water-miscible dye-based ink. Such a color ink-jet printer provides both superior text quality (black ink) and relative ease of service (color inks), since the black ink is used more than the color inks and thus tends to require less spitting due to its frequency of use. On the other hand, since the color inks are used less, the utilization of water-miscible inks, which require less spitting than pigmented inks to keep the nozzle clear, also require less spitting even with relatively lower frequency of use.

Abstract: Ink jet ink compositions consisting essentially of an aqueous carrier medium; an anionic dye; and an anionic polymer have excellent decap and puddling behavior and may be used with a variety of ink jet printers such as continuous, piezoelectric, drop-on-demand and thermal or bubble jet drop-on-demand, and are particularly adapted for use in thermal ink jet printers.

Abstract: A pigmented ink for ink jet printers which comprises an aqueous carrier medium, pigment particles dispersed in an AB or BAB block copolymer having a hydrophilic segment and a segment that links to the pigment, and an effective amount of a surfactant sufficient to decrease the drying time of the ink. The A block and the B block(s) have molecular weights of at least 300. These inks give images having good print quality, water and smear resistance, lightfastness, and storage stability.

Abstract: An ink for ink jet printers which comprises an aqueous carrier medium, pigment dispersion or dye and a polyol/alkylene oxide condensate cosolvent which eliminates film formation on thermal ink jet resistor surfaces thereby eliminating non-uniformity in optical density. The cosolvent present at least 5% has a solubility in water of at least 4.5 parts in 100 parts of water at 25.degree. C. and a general formula: ##STR1## wherein X=--H or --CH.sub.3 ;R=--H, --CH.sub.3, --C.sub.2 H.sub.5, --C.sub.3 H.sub.7, --C.sub.4 H.sub.9, or --CH.sub.2 O(CH.sub.2 CH.sub.2 O).sub.e H;b=0 or 1,a+d+f(c+e)=2-100; andf=1-6, the cosolvent being present in the amount of at least 4.5% based on the total weight of the ink jet ink composition. These inks exhibit freedom from thermal resistor film formation, have excellent decap performance, are storage stable and give images having excellent print quality.