Epson LQ-510 Technical Manual page 69

REV.-A
2.3 PRINTER MECHANISM AND CONTROL CIRCUIT OPERATION
This section describes the operation of printer mechanism and control circuit.
2.3.1 Vx VOLTAGE SUPPLY CIRCUIT
When the +24 V power supply line reaches 11.6 V (11 V + 0.6 V), transistors Q33 and Q34 turn on and
Vx (+ 5 V) is output. On the other hand, if the 24 V power supply line drops to 11.6 V or less, Q33 and Q34
turn off, and the Vx voltage is shut off.
The Vx voltage is used to prevent abnormal operation of the printer when the power is switched on or off.
When the power is switched on or off, the circuit is reset so that it will not drive the printer until the power
supply stabilizes.
These prevent printhead malfunctions when power is switched on or off.
These prevent paper-feed motor malfunctions when power is switched on or off.
LQ-510
+ 2 4 V + 5 V
I
R32
4 3 0
Figure 2-34. Vx Voltage Circuit
PRINCIPLES OF OPERATION
2-27