Epson LQ-2550 Technical Manual page 114

2.3.4.6. PT Sensor Circuit
Figure 2-64 shows the PT sensor circuit. The TCS (Touch Control Sensor) in this circuit detects the paper "'-"'
thickness according to the change in pressure applied by the PT solenoid, and the pressure is changed
the voltage value.This circuit can detect paper thickness between O and 0.8 [mm].
—
- - J
R2
c1
10K (1
0 . 0 luF
*1: Resistor for sensor gain adjustment
Touch control sensor
* 2 :
Potentiometer (VR) for gain adjustment
* 3 :
8 V for constant voltage supply
* 5 : Thermistor for compensating for changes in paper thickness due to changes in temperature
Figure 2-65 shows the relationship between the PW sensor detection value and the voltage at the AN4
terminal of the sub CPU.
+ * 2
.
* 5
TH 1
Figure 2-64. PT Sensor Circuit
Effective paper
thickness detection
range
Paper thickness (T) = 1.66x AN4 terminal voltage (E)
Figure 2-65. Paper Thickness and AN4 Voltage
1
* R 1 O
+
* 3
P a p e r thickness[mm] ~
2-68
+12
CPU
SUB
( 7 8 )
5 ~ CM2-6
A V
T SS