Ink-jet inks with improved colors and plain paper capacity

Claim 2

A dye set for use with thermal ink-jet printers having at least 300 dpi print capability consisting essentially of Acid Yellow 23, Direct Red 227, Acid Blue 9, and Food Black 2.

Claim 3

The dye set of claim 1 wherein Acid Yellow 23 and Direct Red 227 dye molecules are associated with tetramethylammonium cations.

Claim 4

The dye set of claim 1 wherein Food Black 2 dye molecules are associated with lithium cations.

Claim 5

A set of inks containing yellow, magenta, cyan, and black dyes for thermal ink-jet printers having at least 300 dpi print capability, said yellow ink having the formula ______________________________________ Acid Yellow 23 about 0.5 to 5.0 wt % diethylene glycol about 5 to 15 wt % buffer about 0.01 to 0.5 wt % bactericide about 0.1 to 1.0 wt % water balance, ______________________________________ the pH of said yellow ink being adjusted to a value within the range of about 5.5 to 8.5, said magenta ink having the formula ______________________________________ Direct Red 227 about 0.5 to 5.0 wt % diethylene glycol about 5 to 15 wt % bactericide about 0.1 to 1.0 wt % water balance, ______________________________________ said cyan ink having the formula ______________________________________ Acid Blue 9 about 0.5 to 5.0 wt % diethylene glycol about 5 to 15 wt % bactericide about 0.1 to 1.0 wt % water balance, and ______________________________________ said black ink having the formula ______________________________________ Food Black 2 about 0.5 to 5.0 wt % diethylene glycol about 5 to 15 wt % buffer about 0.01 to 0.5 wt % bactericide about 0.05 to 1.0 wt % water balance. ______________________________________

Claim 6

A set of inks containing yellow, magenta, cyan, and black dyes for thermal ink-jet printers having at least 300 dpi print capability, said yellow ink having the formula ______________________________________ Acid Yellow 23 about 0.5 to 5.0 wt % diethylene glycol about 5 to 15 wt % buffer about 0.01 to 0.5 wt % bactericide about 0.1 to 1.0 wt % water balance, ______________________________________ the pH of said yellow ink being adjusted to a value within the range of about 5.5 to 8.5, said magenta ink having the formula ______________________________________ Direct Red 227 about 0.5 to 5.0 wt % diethylene glycol about 5 to 15 wt % bactericide about 0.1 to 1.0 wt % water balance, ______________________________________ said cyan ink having the formula ______________________________________ Acid Blue 9 about 0.5 to 5.0 wt % diethylene glycol about 5 to 15 wt % bactericide about 0.1 to 1.0 wt % water balance, and ______________________________________ said black ink having the formula ______________________________________ Food Black 2 about 0.5 to 5.0 wt % diethylene glycol about 5 to 15 wt % buffer about 0.01 to 0.5 wt % bactericide about 0.05 to 1.0 wt % water balance. ______________________________________

Claim 7

The set of inks of claim 4, said yellow ink having the formula ______________________________________ Acid Yellow 23-TMA about 2.04 wt % diethylene glycol about 5.4 wt % KH.sub.2 PO.sub.4 buffer about 0.08 wt %; bactericide about 0.3 wt % water balance, ______________________________________ the pH of said yellow ink being adjusted to a value of about 7.5, said magenta ink having the formula ______________________________________ Direct Red 227-TMA about 2.95 wt % diethylene glycol about 7.9 wt % bactericide about 0.3 wt % water balance, ______________________________________ said cyan ink having the formula ______________________________________ Acid Blue 9-Na about 1.1 wt % diethylene glycol about 7.9 wt % bactericide about 0.3 wt % water balance, and ______________________________________ said black ink having the formula ______________________________________ Food Black 2-Li about 2.5 wt % diethylene glycol about 5.5 wt % sodium borate about 0.2 wt % buffer bactericide about 0.08 wt % water balance, ______________________________________ where TMA indicates the tetramethylammonium cation associated therewith, Na indicates the sodium cation associated therewith, and Li indicates the lithium cation associated therewith.