Color Ribbon Sensorcircuit; Platen Gapsensorcircuit - Epson LQ-300 Service Manual

2.3.13 Color Ribbon Sensor Circuit
The printer's color ribbon circuitry is shown in the figure below. The CPU receives signals (HIGH
or LOW) from the mechanical switch. The signal is HIGH (ON) when a color ribbon is installed
and is LOW (OFF) otherwise.
CPU (Cl)
Figure 2-25. Color Ribbon
2.3.14 Platen Gap
Sensor Circuit
This printer has a connector switch to sense the PG(Platen Gap) adjust lever position. The CPU
receives a signal from the PG sensor and recognizes the PG adjust lever position. The comector
switch is open(OFF) when the printer is in copy mode(PG adjust lever position:2-6) and is
decrease in copy mode.
Figure 2-26. Platen Gap
+5 v
51
P31
Printer
Sensor Circuit Diagram
CPU (ICI)
1
P54
Sensor Circuit Diagram
Operating PrinciMes
Color Sensor
Ribbon
I
I
2-19