PURPOSE: To enable reduction in the cost of equipment by having a main ink solvent in a container sucked up into a porous member arranged near a nozzle orifice through a conduit.

CONSTITUTION: A porous member 101 is impregnated with a liquid the same as the main solvent of ink in a nozzle 102, which is vaporizing from the surface 107 of the porous member 101. The main solvent of ink after vaporized is replenished by the capillary action through the surface 107 of the porous member. As a result, the main solvent of ink held in a container 108 is sucked up into the surface 107 of the porous member through a conduit 109 and a connection tube 110. Thus, as the vapor of the main solvent of ink ceaselessly exists in the space near the nozzle 102 at a high vapor pressure close to the saturation value, the ink in the nozzle 102 will not dry.