Cationic dyes with added multi-valent cations to reduce bleed in thermal ink-jet inks
AssigneeHewlett-Packard Company
InventorJohn L. Stoffel
Life of this patent
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Abstract
An ink set is provided in which bleed between yellow and black inks is reduced by using a cationic yellow dye in the yellow ink and an anionic dye in the black ink. Bleed is further reduced by adding a multi-valent precipitating agent to the yellow ink. With regard to bleed between yellow and other color inks (cyan and magenta), bleed is reduced by also employing anionic dyes in the color inks.
Claims16
An ink-jet ink set for thermal ink-jet printing comprising cyan, magenta, yellow, and black inks, wherein said black ink includes at least one anionic dye and wherein said yellow ink includes (a) at least one cationic dye and (b) about 1 to 10 wt % of a multi-valent precipitating agent.
A method of reducing color bleed between yellow and other colors in a cyan, magenta, yellow, and black ink dye set, comprising formulating said black ink with at least one anionic dye and formulating said yellow ink with at least one cationic dye and with about 1 to 10 wt % of a multi-valent precipitating agent.
Dependencies are inferred from the claim text.