| 摘要 |
PURPOSE:To prevent the destruction of a thermal head and, at the same time, to attain to enhance the reliability of the titled apparatus, by further providing a plurality of heat generating resistors to the outside of (n) heat generating resistor groups used in printing. CONSTITUTION:The heat generating resistors Ra, Rb formed to both ends of a thermal head part 1 are connected to transistors, which drive heat generating resistors R1, Rn at both terminals of the heat generating resistor group 2 used in printing, through voltage dividing resistors Ra', Rb' and, therefore, when voltage applied to the resistors R1, Rn is set to V, voltages Va, Vb applied to the resistors Ra, Rb come to Va, Vb<V by the voltage dividing resistors Ra', Rb'. By driving the heat generating resistors Ra, Rb in synchronous relation to the heat generating resistors R1, Rn inside said resistors Ra, Rb, the temp. gradient at both ends of the heat generating resistor group 2 can be made gentle and the thermal fatique deterioration of the resistance values of the resistors R1, Rn can be reduced. |
