| 摘要 |
<p>PURPOSE:To enhance a printing speed with a relatively small power source capacity by a method wherein the number of divisions in a time-sharing drive is varied under control in accordance with the number of black printing dots in one-line printing data to be printed so that the number of divisions is reduced to raise a printing speed when the number of black printing dots is small. CONSTITUTION:Serial printing data is inputted from a terminal DATIN in synchronism with a signal CLOCK, and the serial signals are latched in latch circuits of driver ICs 21 - 28 on a signal (-LATCH). Simultaneously, the number of black printing data is counted by an 11-bit binary counter 29 and inputted to a programable logic array (PAL) 30. Thus, signals (-STB1) - (-STB8) are determined. Because the content of the counter is firstly (b11, b10, b8) = (1, 1, 1), an 8-division drive in which the pulses of the signals (-STB1) - (-STB8) are respectively outputted at timings T1 - T8 is conducted. Next, it turns to (b11, b10, b8) = (0, 0, 1), and a 2-division drive is conducted. Moreover, it turns to (b11, b10, b8) = (0, 1, 0), and a 4-division drive is performed. After the comple tion of one-line drive, the PAL 30 outputs a signal END.</p> |
