To solve the problem wherein there is a need for stirring sigment ink for every constant period for preventing the pigment of the pigment ink being precipitate with a time lapse, further a stirring machine must be operated for a certain time for eliminating the precipitation of the pigment ink, thereby printing action or head maintenance order should wait when they comes during that time in an inkjet printer controlling with one motor both a mixing mechanism of an ink tank and a feeding valve mechanism feeding the ink from the ink tank to a printing head through a tube.

The printing action or the head maintenance action need not be wait by making a priority order the same as other movements in first few minutes when an efficiency of the stirring movement is high and by lowering the priority order in the rest time.