Kyocera FS C5020N - Color LED Printer Service Manual page 145

Paper gauge sensing circuit
The actuator which has a light reflector at one end keeps tracking of the height of the paper stack in the paper cassette.
The angle of the reflector varies according to the actuator angle which means the amount of paper remaining. As the
reflector moves across the detecting surface of paper gauge sensor (photo interrupter) 1 and 2, the on and off states of
these sensors vary in combination as shown in the table below, allowing to determine the amount of remaining paper in
the cassette.
Paper feed unit
Sensor PWB
Paper gauge
sensor 1 (PH702)
Paper gauge
sensor 2 (PH703)
Figure 2-1-4
Acutuator
(Reflecting mirror)
Paper
Actuator
gauge
position
Empty
PH702
PH703
1 to 1/3
1/3 to 2/3
2/3 to full
2F3/2F4
Sensing input
PH702 PH703
L L
L
H
H H
L
H
2-1-3