METHOD AND APPARATUS FOR DRIVING THERMAL HEAD

摘要

PURPOSE:To uniformize surface temperatures between heat generating resistors and ultimately the density of images recorded by controlling heating of the heat generating resistors sequentially from smaller resistance value thereof utilizing a heat storage effect of the heat generating resistors due to heat generation in printing. CONSTITUTION:The heat generating section of a thermal head is provided with heat generating resistors R1...Rn in the number corresponding to the number of image elements in the main scanning direction and current is applied to the heat generating resistors R1...Rn according to image signals to perform a recording on a heat sensitive medium by causing the heat generating resistors alone to generate heat. The heat generating resistors are each provided with proper rectifying diodes D to secure an appropriate heat generation while terminals on the diode D side thereof are kept at a constant potentional. The other terminals thereof are provided with AND gates G1...Gn. Thus, a proper printing pulse is applied through the AND gates to effect heat generation of the heat generating resistors only corresponding to image information.