A method of printing a three-dimensional object. The method comprises supplying a print material that is electrically conductive to a plurality of ejector conduits arranged in an array, the ejector conduits comprising first ends configured to accept the print material and second ends comprising ejector nozzles; advancing the print material in one or more of the ejector conduits of the array until the print material is disposed in the ejector nozzle of the one or more ejector conduits; flowing electrical current through the print material positioned in at least one of the ejector nozzles, thereby heating and expanding the print material in the at least one of the ejector nozzles so as to eject at least a portion of the print material from the at least one of the ejector nozzles onto a print substrate; and repeating both the advancing and the flowing electrical current through the print material to form a three-dimensional object on the print substrate.