Patent ID: 7441853

Claim:
An image forming apparatus, comprising: a liquid ejection head which includes a plurality of nozzles and a plurality of pressure generating elements provided correspondingly to the plurality of nozzles, the pressure generating elements being applied with drive signals to eject recording liquid from the corresponding nozzles; a plurality of driving wave generating circuits which generate drive-signal waves for driving the pressure generating elements; a circuit selecting device which switches connection relationships between the pressure generating elements and the driving wave generating circuits so as to selectively apply the drive-signal waves from at least two of the driving wave generating circuits to each of the pressure generating elements; a power source which supplies electricity to the pressure generating elements through the driving wave generating circuits; a connection control device which, in accordance with image data representing an image to be formed, selects at least one of the driving wave generating circuits used to drive the pressure generating elements, and controls connection between the at least one of the driving wave generating circuits and the pressure generating elements, so that instantaneous current consumption of each of the driving wave generating circuits falls within a specific allowable value; and a phase control device which controls phases of the drive-signal waves generated by the driving wave generating circuits so that the instantaneous current consumption at the power source falls within a specific upper limit.