| 摘要 |
A method and ink-jet ink composition are provided for reducing crystallization of Acid Yellow 23 anionic dye in ink-jet ink compositions printed on transparencies and glossy media, both film- and paper-based. The method comprises formulating the yellow ink-jet ink composition in accordance with at least one of the following three conditions: (a) a first condition, wherein the yellow ink-jet ink composition includes about 6 to 9 wt % ethylhydroxypropanediol, about 3 to 9 wt % 2-pyrrolidone, and about 3 to 9 wt % diethylene glycol; (b) a second condition, wherein the vehicle of the yellow ink-jet ink includes a buffer in amount sufficient to maintain the pH of the ink-jet ink within the range of about 5 to 7; and (c) a third condition, wherein the cation of the inorganic salt component of the ink-jet ink comprises calcium ions to the substantial exclusion of magnesium ions. While any or all of the foregoing conditions may be implemented to reduce crystallization in the yellow ink, a combination of the three is particularly efficacious. A narrower embodiment also incorporates two alternative techniques, namely reducing the dye load of the yellow ink to no more than about 3.5 wt % and increasing the thickness of the clear polymeric surface coating of the transparency or glossy media to at least about 12 mu m from its typical 10 mu m. The solution offered by the present method and ink-jet ink composition is easily and inexpensively implemented and does not sacrifice overall print quality.
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