Kyocera KM-4230 Service Manual page 58

Toner hopper lockup detection
The amount of recycled toner in the toner main hopper is monitored by the toner hopper
lockup sensor (TLS). It converts the presence or absence of toner in the toner main
hopper into a voltage and sends it to the main PCB, which prevents toner main hopper
lockup as the amount of the recycled toner in the hopper increases.
Toner feed start level
Toner feed stop level
Toner recycle motor
Toner hopper lockup
sensor output voltage (V)
A When the toner hopper lockup sensor (TLS) output voltage is below 0.5 V, toner is
replenished to control toner density.
B When the toner hopper lockup sensor (TLS) output voltage exceeds 4.5 V while toner
sensor output voltage is below the toner feed start level, toner is not replenished.
C When the toner sensor output voltage is over the toner feed start level while the toner
hopper lockup sensor (TLS) output level is over 4.5 V, the toner feed motor (TFM) does
not operate, while the toner recycle motor (TRM) operates continuously.
D When the toner hopper lockup sensor (TLS) output voltage is over 4.5 V, the on-time of
the toner recycle motor (TRM) is counted. When the continuous on-time exceeds 1 min.,
C740 (toner hopper problem) is displayed.
4.5 V
0.5 V
A
Figure 1-3-32 Toner hopper lockup detection
B
1 min
C D
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