| 摘要 |
A process is provided for purifying macromolecular chromophores (MMCs), which are pigments that have been surface-treated to be water-soluble. In the surface treatment, anionic or cationic functional groups are covalently bonded onto the surface, these functional groups have undesirable counter-ions associated with them that adversely affect the properties of ink-jet inks in which the MMCs are incorporated. The purification process comprises: (a) forming an aqueous solution of the macro-molecular chromophore; (b) adding to the aqueous solution an amount of a liquid containing a desirable counter-ion; (c) subjecting the aqueous solution to membrane filtration; and (d) repeating steps (b) and (c). Inks prepared from MMCs that are purified as described above evidence significant improvement in reliability, which includes reduced crusting, reduced kogation, and improved long term ink stability.
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