| 摘要 |
PURPOSE:To hardly receive the effect of ambient temperature, by providing a heat-detecting sensor and increasing/decreasing the number of pulses according to the ambient temperature for giving the pulses to a heating resistor. CONSTITUTION:RAMs 5, 6 are read out alternately with an output pulse of a selection controller 20 having a period of one line interval, the write is done, and a picture signal of each line is outputted for a prescribed number of times from a data selector 7. A data comparator 8 compares an input picture signal with an output of an ROM selecting device 10 selecting grading designation data ROMs 11, 12, 13, and ''1'' is given to a shift register of a thermal head only for dot being picture signal >grading designation data, and a voltage is applied to the dot given with ''1'' in one line. That is, the number of voltage application to the dots of the head is changed depending on the picture signal. Which of the ROMs 11, 12, 13 is selected by the ROM selecting device 10 depends on an output signal of comparators 15, 17 or an NOR gate 18 taking the output of the detector 14 as the input. |
