Kyocera FS-1900 Service Manual page 88

A toner sensor is provided within the developer. As the toner supply from the toner container
dwindles and the toner level lowers in the reservoir, the sensor translates it into an electrical signal
through its diaphragm, urging the toner motor to feed more toner.
Toner container
Toner hopper
Toner motor
Sensable level
Toner sensor
Diaphragm
Toner
Developer
Figure 4-1-11 Toner sensor
FS-1900
4-13