Carriage Motor Driving Circuit - Star Micronics NX-1020 Technical Manual

THEORY OF OPERATION

2-2-4. Carriage Motor Driving Circuit

This printer employs a stepping motor as the carriage motor. Unlike regular motors on the market, this stepping motor
will not operate just by connecting it to a power source. The motor operates only when a drive pulse is fed to it, but even
then, it turns only a certain angle. This stepping motor is characterized by 4-phase stepping. Control of the motor is
facilitated by phase 1-2 excitation. The following shows the carriage motor drive circuit and the control signal generated
by the phase 1-2 excitation method.
The utilization of voltage applied to the carriage motor is
described below:
Voltage applied to the carriage motor is changed by setting
port P30 of the CPU to HIGH or LOW and by turning
transistors TR1 and TR6 ON or OFF.
When TR6 is ON, +25V is supplied to the carriage motor
and when TR6 is OFF, +5V is supplied to the motor via
diode D3.
Fig. 2-9 Print Head Temperature Detection Circuit
Fig. 2-10 Carriage Motor Driving Circuit
Fig. 2-11 Carriage Motor Driving Signals
– 26 –
Mode Voltage
Operation: +25VDC
Standby: +5VDC
Application
Motor Drive
Holding Bias