| 摘要 |
PURPOSE:To reduce the lowering in printing quality while making density irregularity hardly conspicuous, by providing a plurality of heat generators between a pair of electrodes and forming recording dots into arrangement having level difference in an auxiliary scanning direction, by slightly shifting adjacent heat generators in the auxiliary direction. CONSTITUTION:A thermal head 2 is constituted so that a heat generating resistor element 2a is divided into three heat generators 2a1, 2a2, 2a3 which are, in turn, respectively connected to a common electrode 2b and individual electrodes 2c so as to provide a shift amount (l) between adjacent heat generators in an auxiliary scanning direction. Printing dots are brought to such a state that level difference is generated by DELTAl' corresponding to the shift amount (l) in the auxiliary direction and front and rear auxiliary scanning lines mutually relate by DELTAl'. When a voltage applying time is shortened and the heat generating resistor element 2a is driven to generate heat, each printing dot becomes small and a color developing ratio is also lowered to obtain low density printing. Because the printing dots are shifted in the auxiliary scanning direction, printing dot intervals A do not become linear and dispersed to the auxiliary scanning direction in the printing dot unit corresponding to the heat generators 2a1, 2a2, 2a3 to be made inconspicuous and the lowering in printing quality can be reduced. |
