Ink composition containing a particular type of dye, and corresponding ink jet printing process

PROBLEM TO BE SOLVED: To provide a new ink composition having improved light fastness, an ink jet printing process using the ink, and an ink jet apparatus comprising a cartridge containing the ink composition. SOLUTION: This ink composition contains a new type dye (DYE)n (SAU)m assembling under an appropriate condition, assembling with other analogous dye (DYE')n '(SAU')m ', or assembling with a compound (SAU)p (X)q to form a supermolecular structure. The ink jet printing process uses the new dye. The ink jet printing apparatus is equipped with the ink cartridge containing the dye.