PURPOSE: To ensure the assured printing even in case the number of the printing digit is large or other additional processes are required, by performing the comparison between the character contents and the printing in the cycle of one preceding character timing.

CONSTITUTION: The printing board possessing equidistantly the plural number of characters over the entire circumference is driven in the equal speed, and two units of the timing pulses featuring the short and long cycles in the front and rear parts respectively are produced with every character. In such driving system for the printer, the comparison is given between the next character contents and the printing data during the long-cycle timing pulse. And in case the agreement is obtained, the print driving is carried out during the next long-cycle timing pulse. And only the control is given to the magnet output terminal in the short part of the cycle of the timing pulse. These control are carried out in a soft way via the 1-chip type CPU.