Correcting The Output At The Trailing Edge Of Paper - Canon GP605 Service Manual

3.

Correcting the Output at the Trailing Edge of Paper

When paper moves through the transfer charging assembly, the resistance abruptly drops as
soon as the paper leaves the assembly, possibly causing discharge current momentarily and, ulti-
mately, leading to white spots or distorted images. To prevent such a problem, the transfer current
level is corrected (reduced) when the trailing edge of paper passes.
Feeding direction
In a low humidity environment, paper tends to dry
up collecting excess charges (high resistance); to
counter, the output is reduced.
Low humidity
Normal humidity
High humidity
Related Service Mode
COPIER>OPTION>BODY>
TRSW-P-B
(transfer current output correction
control ON/OFF)
COPYRIGHT © 1999 CANON INC.
The output of the transfer current is
varied over a width of 20 mm along
the trailing edge of paper.
Paper
Figure 6-311 Trailing Edge of Paper
When making a double-sided print, paper will absorb fixing
oil and tend to collect less charges (low resistance); since
the discharge current along the trailing edge of paper will
be low, the output is not varied.
Transfer current correction (µA)
Single-sided copying
+220
+150
Table 6-302
1: do not vary the transfer current level. (default; select if
transfer faults occur along the trailing edge)
0: correct the transfer current level along the trailing edge of
paper.
CANON GP605/605V REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 6 IMAGE FORMATION SYSTEM
20 mm
Double-sided copying
6-29