PURPOSE: To increase an efficiency of heat conductivity to ink, to decrease a response time, and in addition, to increase a discharge pressure of an ink droplet, to increase its flying speed, and to obtain an accurate adherence of the ink droplet by providing a reflective layer of rays in an infrared region on an inner periphery of a chamber in which a heat transformation body is provided in a recording head of an on-demand type ink-jet printer.

CONSTITUTION: Heat generating bodies 6 and electrodes 5 for application of electricity are provided on a substrate 4, and the heat generating bodies 6 are joined by an adhesive to the grooves formed in a grooved cover 1 to properly fit therein. An energy application chamber in which thermal energy is applied to the ink is provided on a heat generating portion of an electric heat transformation body. On the interior wall of the energy application chamber on which the thermal energy is applied to a fluid by the heat generaing body 6, a reflective layer 7 which reflects rays in a region that includes an infrared ray is provided. The layer which reflects rays in the region which includes the infrared ray is preferably a layer which reflects rays over 700nm, the most pref. rays above 810nm, however, it could be the one which reflects only so called heat rays.