Potential Control During High Humidity Mode - Canon GP605 Service Manual

CHAPTER 6 IMAGE FORMATION SYSTEM
2.

Potential Control during High Humidity Mode

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.
Potential sensor
Laser
Grid bias
Potential determined
Related Service Mode
COPIER>OPTION>BODY>
CNT-W/HM
(high humidity mode potential control
setting)
Main power switch
Set
OFF/ON
COPIER > OPTION > BODY > CNT-W/HM
6-14
COPYRIGHT © 1999 CANON INC.
Lighter
Extra low humidity
Low humidity
Density
Normal humidity
High humidity
Darker
Extra high humidity
Potential control
sequence started
195˚C
WMUP WMUPR
VD
Vg
Vg
Figure 6-212 Sequence of Operations
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
Potential control
Table 6-203 Timing of Control
CANON GP605/605V REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Laser power
correction
value
-5%
+5%
The laser power/Vdc is corrected
to suit the environment.
VL
Pw
Pw
Vdc
The laser power/Vdc suited to
the environment is updated
each time the Copy Start key is
pressed.
Copy Start
key ON
Vdc
VD
correction
correction
value
value
+20V
+30V
200˚C
STBY