In a structure in which a printing medium is subjected to a maintenance ejection in order to maintain a favorable ink ejection performance of a printing head, dots formed on the printing medium by the maintenance ejection have a reduced visibility. Specifically, an area of dots formed by landing ink droplets ejected from the printing head for the maintenance ejection onto the printing medium is smaller than an area of similar dots formed by a normal printing. Specifically, by flowing currents having different waveforms into an ejection heater of the printing head depending on the ejection for printing an image and the maintenance ejection, an area of dots formed by the maintenance ejection can be smaller than an area of dots formed by the normal ejection for printing an image.