PURPOSE: To achieve security of a stable uniform driving state not to be influenced by ambient temperature difference and shortening of ink drying time by a method wherein a heater is installed to a comb-type thermal transfer member having a plurality of thermal transfer surfaces, and the thermal transfer member is so installed that the thermal transfer surfaces face vibration boards of a plurality of subheads.

CONSTITUTION: Two subheads are in a row arranged, and a heater 11 is installed to a comb root outer peripheral surface of a comb-state thermal transfer member 10 composed of metal in material. Then, the thermal transfer member 10 is installed to a position so that a thermal transfer surface 13 equal to a comb inner peripheral surface of the thermal transfer member 10 faces all vibration boards 6 of two subheads 9 and a gap between the vibration board 6 and the thermal transfer surface 13 becomes uniform. When the heater 11 is electrified, temperature of the thermal transfer member 10 of which thermal conductivity is high rises quickly and it is heated to a state in which temperature gradient is partially small. Then, heat is transmitted from the thermal transfer surface 13 of the thermal transfer member 10 to the vibration board 6 through the gap, and ink is heated via a path peripheral surface. Since a supply place of the ink to which heat is thus supplied is the path interconnected near a nozzle 1, heat quantity loss to the nozzle 1 can be extremely reduced.