In an apparatus to perform printing by ejecting an ink and a printing quality improving liquid for making a coloring agent in the ink insoluble or coagulated, reaction between the printing quality improving liquid and the coloring agent of the ink is certainly caused. Namely, after ejecting the printing quality improving liquid from a head, Bk ink, Y ink, M ink and C ink are ejected through heads within a given period, e.g. 500 msec. By this, the printing quality improving liquid may react with the coloring agent of the ink before penetrating into a printing medium to certainly make the coloring agent insoluble or coagulated.