| 摘要 |
PURPOSE:To obtain image quality having the same density by eliminating difference in printing density caused by irregularity in the resistance of a thermal head, by writing the data based on the irregularity in information of the average resistance value and resistance value of the thermal head into a memory element and controlling a printing time on the basis of said data. CONSTITUTION:When a mode change-over signal S1 is outputted, five bits of irregularity informations stored in RAM1 are successively read from RAM1 in the rise timing of a clock signal to be inputted to CPU5. CPU5 receives this RAM data to input the 8-bit data which is compared with data obtained by counting up a reference clock generating circuit 6 with a counter 7 to a comparator 9 through a latch circuit 8. The data showing the printing time corresponding to one gradation calculated by CPU5 is outputted to the latch circuit 8 for input to the comparator 9. The output of the counter 7 is inputted to the comparator 9 and, when these outputs coincide, a latch signal is outputted to a thermal head through an one shot circuit 10 to control the increase and decrease of a printing time being one of printing conditions. |
