In a printing apparatus for forming a desired image by coagulating a portion of liquid ink in a predetermined space S formed between a circumferential surface of a rotation drum and a plurality of negative electrodes by electrical energizing, and transferring this to a printing object such as paper, to thereby affect printing, there is provided on a rotation input side of the plurality of negative electrodes a discharge port whereby a fluid can be discharged towards the negative electrode surface and the surroundings thereof. Moreover, there is provided a fluid supply device for supplying a fluid (which may be a liquid or a gas) to the discharge port.