To reduce the fluctuation of speed of hammer bank to reduce vibration and noise of a dot line printer body, thereby to effect printing of high quality by restraining fluctuation of speed generated in a shuttle mechanism, without increasing number of parts, that is, the size and cost of machines, and without lowering printing speed in comparison with trapezoidal waveform control, so that smooth shuttle action can be achieved.
In a shuttle mechanism of a dot line printer, when a hammer bank 2 is transferred from an accelerating state to a constant speed state, the phase switching speed of a stepping motor 5 is lowered below an ideal drive speed of the hammer bank 2 achieved by trapezoidal waveform control, by about a quarter of a previously measured cycle of fluctuation of speed of the bank 2, and at the same time the phase switching speed is controlled so as not to become lower than a speed before the bank 2 was transferred.
KAWAMICHI GENICHIRO
KIKUCHI MUNEYUKI
YAMADA MAKOTO
