Canon 1000 Service Manual page 162

3. OPERATION AND TIMING
As shown in Figure 3-549, the hopper consists of a main hopper and a sub hopper. Bk toner requires
higher precision than color toner for supply operation because its amount of supply is based on a value
computed from video signals. To ensure precision, the main hopper, in which toner tends to cake less, is
used to supply toner to the developing assembly.
Toner level sensor
(upper)
(TS4)
Toner level
sensor (lower)
(TS5)
If the results of measuring the toner density indicate that the density of toner inside the developing
assembly is below a specific value, the DC controller sends the toner supply signal to turn on the toner
supply clutch. As a result, the drive of the Pick-up motor will be transmitted to the toner supply screw to
supply the developing assembly with toner.
The toner density signal is used to determine how long toner should be supplied, i.e., how long the toner
supply clutch should remain on.
3-118
COPYRIGHT © 2001 CANON INC.
Toner supply
clutch (upper)
Toner supply (upper) signal (CL4D*)
CL4 Pick-up motor
drive signal (M10MD)
M10
CL5
Pick-up motor toner supply
(lower) signal (CL5D*)
Toner supply
clutch (lower)
Toner level detection (lower) signal (BKTEPL*)
Toner level detection (upper) signal (BKTEPU*)
Figure 3-549
CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
DC
controller
PCB