An inkjet printing apparatus for forming images with ink droplets includes the following elements: an inkjet head, a plurality of holders for removably holding a plurality of ink tanks storing inks interchangeable with each other, branch pipes each having one end thereof connected to one of the ink tanks, a mixer provided at the other ends of the branch pipes, a pump for feeding the inks to the mixer, a feed pipe connecting the mixer and the inkjet head, and a controller for controlling ink feeding. The controller makes different a feed rate of the ink from each of the ink tanks.