| 摘要 |
<p>PURPOSE:To prevent the damage of a recording element or the deterioration of recording quality when the control part operated by software is operated abnormally, by providing the circuit of hardware for limiting the width of a driving signal within a predetermined range. CONSTITUTION:Even when CPU is abnormally operated and a timer starting signal TK is brought to a DC state while strobe signals STB1-4 outputted to a strobe signal driver 213 from the third output port 205 of an output IC200, a timer 210 alternately outputs a timer on-operation signal TD and time-up signal TA. A counter 211 also outputs count signals C1, C2 and a decoder 212 also ouputs decoder output signals DC1-DC4 to the strobe signal driver 213. Because the strobe signal driver 213 outputs the AND signals of the decoder output signals DC1-DC4 and the strobe signals STB1-4 to a thermal head as strobe signals STB1'-4', the outputted strobe signals STB1'-4' become same to the strobe signals STB1-4 in a normal state and the driving of heat generation elements R1-R1728 are performed so as not to be different from a normal state.</p> |
