Jet ink and process for preparing dispersion of colored fine particles for jet ink

Abstract

An aqueous jet ink which is provided with a long-term dispersion stability, a stable emission property as a ink-jet stream, and good adhesion of printed images to the recording medium. The present jet ink is constituted as an aqueous liquid dispersion of fine color particles which are formed by coating fine pigment particles (a) with a coat forming resin having carboxyl groups (b). The surface of the color particles is covered with the quaternary carboxyl groups in a form of quaternary ammonium salt and the average volume diameter of the fine color particles is restricted to less than 0.5 .mu.m. An increase rate of the average volume diameter of the fine color particles when the dried ink is dispersed again in water is also restricted to less than 50%.

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