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The waste toner container has a light guide and a waste toner level sensor (PS13) on the
top. The light from the light emitter on the PS13 is let in to the waste toner container through
the light guide attached to the cartridge. It passes through the container and goes back
through the light guide when the light receiver on the PS13 detects the light. Upon detection
of light, the receiver sends a WASTE TONER FULL DETECTION signal (/WTNSNS) to the
DC controller. When the toner level is low, the light will not be interrupted by the toner so it
reaches the light receiver, and vice versa when the toner level is high.
The DC controller judges the waste toner full and sends a “Waste toner full warning 1” to the
formatter when the light does not reach the receiver on the PS13 (that is, when the /
WTNSNS signal is not output). The DC controller then counts the number of prints upon
receipt of warning 1. It sends a “Waste toner full warning 2” after the specified number of
print, determine it full.
DC controller PCB
WASTE TONER FULL DETECTION
signal (/WTNSNS)
< Waste toner not full >
< Waste toner full >
Light
receiver
Light
emitter
Waste toner
full sensor
PS13
Light guide Waste toner container
Waste toner
Figure 5-46.
Waste toner full detection
Transfer (ITB) unit detection
The printer detects the presence of the transfer unit.
The DC controller monitors the waste toner full sensor (PS13) and color misregistration
sensor (PS12) during initial rotation for detection of the ITB unit.
At the start of a print operation, the DC controller lets the PS12 and PS13 emit light. If the
transfer unit is present, the LED light is received at the light receivers on the sensors, and
vice versa.
168 Chapter 5 Theory of operation ENWW