Abstract: A printer for use with a portable calculator, a handy typewriter or the like is provided with a printing control device which comprises a control circuit for controlling the operation of a stepping motor to feed a recording medium. In order to control the motor, the control circuit generates a series of printing control signals and stepping control signals which include an initial stepping control pulse and a final stepping control pulse. Before printing is started, the motor is stepped forwardly with the initial control pulse and is set in an initial condition to make a space preceding a character to be printed on the recording medium. After the printing of one character is performed, the motor is stepped forwardly with the last stepping control pulse to make sufficient space between adjacent characters to be recorded on the recording medium.

Abstract: To adjust the density of alphanumeric to be thermally printed by a thermal printer, a time duration for applying the row or column drive current to the selected dot elements in a thermal head is varied so as to vary a time duration for which the selected dot elements are energized, to thereby change the quantity of heat dissipated therefrom depending upon the environmental temperature, the thermal characteristics and aging of thermally sensitive paper and so forth. The drive current flowing duration may be varied by varying a cycle of the drive current signals to be sequentially applied to the row or column drive lines of a dot element matrix circuit through a character generator. In one embodiment of the present invention, the cycle of the drive current signals may be varied by the frequency division or count down of the clock pulses with a variable pulse repetitive rate used in an electronic computer.

Abstract: A voltage regulator which includes an electrical circuit for maintaining a constant output, said electrical circuit including at least one light emitting diode connected to provide a reference voltage and to operate as a pilot lamp.