Canon 1000 Service Manual page 161

g. Supplying Bk Toner
As shown in Figure 3-547, the sequence of supply operations is based on the detection of the density of
the image and the measurement of the density taken by the SALT sensor.
When the original has been exposed, the video signals are counted, and the toner supply period is
determined based on the cumulative count.
When copying operation ends, the SALT sensor measures the density of toner on the photosensitive
drum is measured. If the resulting measurement is higher than the ideal density (too much toner), a
subtraction will be made from the count of video signals so that the supply period (amount) will be less; if the
measurement is lower than the ideal density (too little toner), on the other hand, opposite correction is made
to supply a larger amount of toner.
Start key
ON
COPY
Original exposed
Video signal counted
Toner supply period determined
The toner density is measured by the SALT sensor as follows. When making single copies,
measurements are taken each time copying ends; in continuous copying, measurements are taken when all
copies have been made. However, if the copy count is set to '100' or higher, measurements are taken when
the 100th copy has been made. (See Figure 3-548.)
4 copies
210 copies
Toner density
measurement
COPYRIGHT © 2001 CANON INC.
Toner supplied Toner density measured
by SALT sensor
1st 2nd 3rd
1st
100th 101st
CANON CLC1000/1000S/3100 REV.2 MAY 2001 PRINTED IN JAPAN (IMPRIME AU JAPON)
Start key
ON
LSTR STBY
Figure 3-547
4th
199th 200th
Figure 3-548
3. OPERATION AND TIMING
COPY
Original exposed Toner supplied
Video signal counted
Toner supply period determined
201st 210th
3-117