Epson LQ-2550 Technical Manual page 113

Upper limit
Lower limit
2.3.4.5 PW
Sensor Circuit
Figure 2-63 shows the PW sensor circuit. This sensor becomes active when the paper thickness exceeds
0.18 [mm] (a postcard or envelop). The paper width is detected by this sensor, and carriage movement
is controlled so that printing is executed to within 1/2 inch from either end of the paper.
\
SUB CPU
— CM2-7
(7 B)
AV
SS
Table 2-42 shows the relationship between the PW sensor detection position and the voltage at the
Temperature ["C]
+ 5 C N 9
1
1
Y
1
1
1
1
1
Figure 2-63. PW Sensor Circuit
Table 2-42. Paper State and AN3 Voltage Level
Detection Position
Paper
Platen
9 0
8 0
180
A
1
1
2 - 6 7
2.71
2 . 8 0
Paper: Reflection
1.
2. Platen: No reflection
H
L