HP 3500 Series

ENWW Image formation system 161
Waste toner full detection
The DC controller monitors the waste toner full sensor (PS13) when the power is turned on, a door
is closed, and a print is completed.
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.
Figure 5-45 Waste toner full detection
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