| 摘要 |
PURPOSE:To obtain a thermal-type printer capable of accurately representing gradations while using a low-capacity ROM, by composing an energizing pulse generation counter of circuits for generating long and short energizing pulses. CONSTITUTION:A gradation counter 2 counts the number of gradations of an image to be printed, and sends gradation data to a comparator 1, a ROM 4 and a zero gradation decoding part 3. The comparator 1 compares input data with the gradation data, and sends data to a shift register 6. Supplied with the gradation data, the ROM 4 sends energizing pulse width data according to the gradation to long and short energizing pulse generating circuits 19, 20. At the time of zero gradation, the long energizing pulse generating circuit 19 is operated to supply long pulses to a switch group 8. At other times, the short energizing pulse generating circuit 20 is operated to generate short energizing pulses according to the energizing pulse width data stored in the ROM 4, and the short pulses are sent to the switch group 8 to open and close switches. |
