Paper End Sensor Circuit - Citizen CBM-710/720 Service Manual

6.

Paper End Sensor Circuit

Fig. 6-1 shows the paper end sensor circuit. The reflection type photo-interrupter is used as a sensor. When some
paper is still left, the light reflected by paper strikes upon the photo-transistor; thus, the collector of the photo-
transistor is L. When paper becomes short, no light is reflected, causing the collector to go H. As a result, the CPU
input port P40 becomes H, going into the paper end state.
Paper End Sensor
PHI 1
Fig. 6-1 Paper End Sensor Circuit
Control Circuit
Vcc
R15
R12
R13
C11 Tr3
R14
13
CBM-710/720 Service Manual
CPU
P40