Panasonic KX-MB2061CXB Service Manual page 65

6.14.10. Toner Sensor.... "Toner Empty", "Toner Low", "Change Drum"
The Sensor detects whether or not the Drum cartridge and the toner are present.
When there is not Drum cartridge, Magnetic Field Sensor IC (IC51) turns off, and the input signal of IC300-AE22pin (Main
Board) becomes a High level over 9s. When the Drum cartridge is set, Magnetic Field Sensor IC (IC51) turns ON/OFF. If the
time of IC300-AE22pin's Low level is under 600ms, there is enough toner in Drum cartridge, if not, toner is near empty.
Toner Sensor
The rest of toner is detected by the move speed of the magnet put on the pendulum of Mixing Paddle. The pendulum is pushed
up by the Mixing Paddle, then it falls down by its own weight. The rotation speed of paddle is set slower than the one of pendu-
lum which falls down by its own weight. When the toner is still left, the pendulum falls and stops on the toner, then pushed by the
paddle, it starts to rotate. When no toner is left, the pendulum falls to the bottom. Consequently the contact time between the
magnet and Magnetic Field sensor IC becomes short when toner is left and long with no toner.
State
Toner Set (full)
Near Empty Toner
Mixing Paddle does not rotate
("CHANGE DRUM")
Display
-
TONER LOW
CHANGE DRUM
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KX-MB2061CXB/KX-MB2061CX2/KX-MB2062CXB
Signal (IC300-AE22pin)
level = about 0.3s
Low level>540ms
High level fix or Low level fix