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THEORY OF OPERATION
Fig. 2-9 Print Head Temperature Detection Circuit
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.
Fig. 2-10 Carriage Motor Driving Circuit
Fig. 2-11 Carriage Motor Driving Signals
The utilization of voltage applied to the carriage motor is described below:
Voltage applied to the carriage motor is changed by setting
terminal CMNA and CMNB of the gate array to HIGH or LOW
and by turning transistors TR5 and TR7 ON or OFF.
When TR5 and TR7 is ON, +25.5V is supplied to the carriage
motor and when TR5 and TR7 is OFF, +5V is supplied to the
motor via diode D3 and D4.
Mode Voltage Application
Operation: VH (+25.5V) Motor Drive
Standby: VL (+5V) Holding Bias
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