- HP Printer User Manual

ENWW Toner supply unit 71
MFP unit explanation
faces downward, toner flows out of the
outlet into the agitation/conveyance
section of the toner supply unit.
Toner level detection control
Toner level detection is controlled by the
TLD (toner level detection sensor) and the
PRCB (printer control board).
1 Operation
a Toner level detection
A piezoelectric device is used as the
TLD (toner level detection sensor).
When the level of toner in the hopper
becomes low, the toner supply signal is
output to PRCB (printer control board).
As a result, a message is displayed on
the LCD connected to OB1 (operation
board/1).
b Detection timing
The detection timing is as follows:
• Power-on
• When the front door opens or closes
• During copying
c Toner supply to toner supply unit
When the no toner state is detected by
TLD (toner level detection sensor), M13
(toner bottle) is turned on to supply
toner from the toner bottle to the toner
supply unit.
d Detection of no toner state in toner
bottle
If the no toner state is detected by TLD
(toner level detection) after M13 has
been held on for a specified period of
time, the toner bottle is assumed to be
empty.
2 Signals
a Input signals
1 TONER_SIG (TLD to PRCB)
When the level of toner in the toner
supply unit becomes low, this signal
goes low ([L]), displaying a message
on the LCD connected to OB1
(operation board/1).
2 TONERM_EM (M13 to PRCB)
M13 (toner bottle) abnormality
detection signal
[L]: M13 is normal.
[H]: M13 is abnormal.
b Output signals
1 T_SENSE_CONT (PRCB to TLD)
TLD (toner level detection sensor)
power control signal
The TLD is powered only when it is
detecting the toner level.
Outlet
90
rotation
To agitation/conveyance block
of toner supply unit
PRCB
DCPS
24V2
P.GND
MS1 MS2
M13
TLD
5V
P.GND
TONERM CONT
TONERM CLK
TONERM CW/CCW
TONERM EM
S.GND
TONER SIG
T SENSE CONT