Patent ID: 8333462
Filing Date: 2012-12-18
Classification: B41J

Abstract:
1. An ink jet printer which performs a print process by ejecting ink for each of a plurality of ink colors, the ink jet printer comprising: a plurality of ink jet heads provided for the plurality of ink colors respectively, each ink jet head being provided with an ink ejection unit set; a plurality of ink circulation routes provided for the plurality of ink colors respectively, each ink circulation route including the ink jet head corresponding thereto; an ink agitating operation drive signal generation unit operable to generate an ink agitating operation drive signal to be applied to the ink ejecting unit sets of the ink jet heads, to make ink agitating operation to the extent that ink is not ejected, in advance of starting the print process; and an ink circulation control unit operable to control ink circulation in the ink circulation routes, wherein the ink circulation control unit starts ink circulation in advance of starting the print process, wherein, after starting the ink circulation, the ink agitating operation drive signal generation unit applies the ink agitating operation drive signal, having a first predetermined first period, to the ink ejecting unit set operable to eject an ink, which has a predetermined nature, for a predetermined first ink agitating operation time, and repeating this application of the ink agitating operation drive signal with a break period before each repetition, wherein, when a predetermined second circulation time elapses from a start of ink circulation, the ink agitating operation drive signal generation unit applies the ink agitating operation drive signal, having a predetermined second period shorter than the first period, to the ink ejecting unit set operable to eject an ink, which does not have the predetermined nature, for a predetermined third ink agitating operation time which is longer than the first ink agitating operation time.