Canon NP6085 Service Manual page 127

2. Detecting the Level of Toner and Controlling
the Supply
The toner inside the developing assembly is
checked by the black toner sensor (Q85) at inter-
vals of 1 sec; the sensor sends the black toner
supply signal BTS=0 to the DC controller when
the level of toner inside the developing assembly
falls below a specific level while the developing
clutch (CL1) is on during copying operation.
Copy Start key ON
Hopper motor (M18)
Black toner supply
signal (BTS)
Hopper toner level
detection signal (TEP)
*1 Supply starts upon detection of black toner supply signal=0.
*2 Supply stops upon detection of black toner supply signal=1.
COPYRIGHT © 1996 CANON INC.
INTR SCFW SCRV SCFW
*1
*2
CANON NP6085 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)
The DC controller PCB generates the hopper
motor drive signal (
supplying toner to the developing assembly.
If the black toner sensor (Q85) becomes faulty
for some reason or if the black toner supply signal
BTS=0 is detected for 120 sec or more without a
required amount of toner from the hopper, the
copier will indicate 'E020' and stop its operation.
Add Toner indicator ON
SCRV LSTR
Figure 3-324
3. OPERATIONS AND TIMING
) to drive M18, thereby
HMD
Add Toner indicator OFF
STBY
Toner supply
3-69