JPS5789975A - Impact type dot matrix printer - Google Patents

Abstract

PURPOSE:To make thickness of printing stable by using a constant current for driving current and a constant impacting energy for printing needle, by selecting a moving number driving signal on the basis of information of a current passing memory signal, and then, by controlling a current value, a current passing time and a delay time. CONSTITUTION:A current passing memory circuit 406, which memorizes for a certain period of time whether or not current is passing to a coil which actuates a printing needle, a driving signal making circuit 405, which makes first and second driving signals of large pulse width and third driving signal of small pulse width, and a driving signal selecting circuit 407, which selects the first and second driving signals and the third driving signal on the basis of an information of the circuit 406 and uses it as a moving member driving signal, are provided as an electromagnetic driving step for a printing needle. And, if content of the circuit 406 proved to be an information indicating no current is passing to a coil 1 dot before, the first driving signal is selected and then the third driving signal is selected, and if the information indicates passing of current to the coil 1 dot before, the second driving signal and the third driving signals are selected consecutively after the selection of the third driving signal.