With regard to a liquid ink-jet recording solution, required is that it conforms with the used recording method, its image tone is good at high recording image density, it can be fixed to the printed medium without bleeding after printing, it is superior in stability as ink, it has no problems of toxicity and inflammability, and its cost is low. From these points of view, many ink-jet inks and the recording methods have been proposed and investigated, resulting in that a quite limited ink-jet recording liquid solution which only satisfies some of the requirements at the same time.
As to color image requiring yellow, magenta, cyan and black, commonly known dyes and pigments having C. I. (Color Index) Numbers described in the C. I. have been widely investigated. Specifically, with regard to magenta ink-jet recording liquid solutions, those, which are using xanthene types (such as C. I. Red 52) or azo types (such as C. I. Acid Red 249) water-soluble dyes, are widely known, but generally have problems of color fading in light and other problems.
Further, it does not become a problem with sheets for ink-jet use, but it is commonly known that uneven bleeding is generated in the fringes of images with sheets for non-ink-jet use such as plain copying paper.
USPTO Backgrounds
USPTO Backgrounds