Canon GP605, Service Manual

Page: 184 / 876

CHAPTER 6 IMAGE FORMATION SYSTEM
6-14
COPYRIGHT © 1999 CANON INC. CANON GP605/605V REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Table 6-203 Timing of Control
Figure 6-212 Sequence of Operations
2. Potential Control during High Humidity Mode
WMUPR WMUP STBY
195˚C
200˚C
Potential sensor
Laser
Grid bias
Vg Pw
VD VL
Potential determined
Vg
Pw
Vdc
Extra low humidity
Low humidity
Normal humidity
High humidity
-5%
+5%
+20V
+30V
Density
Darker
Lighter
In a low humidity environment,
the resistance of paper
decreases and, on the other
hand, the transfer efficiency
increases; as such, the laser
power is reduced to prevent
excess deposit of toner.
In a high humidity environment,
the moisture of paper decreases
the transfer efficiency; as such,
the laser power is increased to
increase the density.
Laser power
correction
value Vdc
correction
value VD
correction
value
Extra high humidity
Potential control
sequence started
The laser power/Vdc is corrected
to suit the environment.
1: correct the laser power/developing bias to suit the
environment (default)
0: disable correction of the target value
2: extra low humidity mode (See the above figure.)
3: low humidity mode (See the above figure.)
4: normal humidity mode (See the above figure.)
5: high humidity mode (See the above figure.)
6: extra high humidity mode (See the above figure.)
7: laser power corrective value +15%
Vdc correction value +40 V
VD correction value 0 V
COPIER>OPTION>BODY>
CNT-W/HM
(high humidity mode potential control
setting)
Related Service Mode
Potential control
COPIER > OPTION > BODY > CNT-W/HM
Set
Main power switch
OFF/ON
The laser power/Vdc suited to
the environment is updated
each time the Copy Start key is
pressed.
Copy Start
key ON