PURPOSE: To enable a high speed printing preventing blurring of printing by arranging Peltier elements on a substrate so that current flows through Peltier elements adjacent to heating Peltier elements in the opposite direction for cooling.

CONSTITUTION: Peltier elements 12 and 13 are arranged alternately on a substrate 11 with one ends of the elements 12 connected to a common electrode 18 through a common conductor 14 while the other ends thereof connected to individual electrodes 19 through separate conductors 16. One ends of the elements 13 are connected to an electrode 21 through a common conducter 15 while the other ends thereof to individual electrodes 20 through separate conductors 17. When voltage is applied between the electrodes 19 and 18 to generate heat from the elements 12, an opposite voltage is applied between the electrodes 20 and 21 to run current through the elements 13 in the opposite direction. Therefore, the elements 13 are cooled when the elements 12 generate heat, which keeps heat generated by the elements 12 from transmitting through the substrate or the like to heat other parts of a heat-sensitive paper.