Density Adjustment During Printing - Canon GP605 Service Manual

CHAPTER 4 IMAGE PROCESSING SYSTEM
2.

Density Adjustment during Printing

The image data is in binary form when printing starts, and the data does not possess density
information. To adjust the density of images during printing, the copier corrects the laser intensity
and the developing bias as follows:
Corrects the laser powerand the developing bias
according to the selected F value.
The laser power is increased to
ensure firm toner deposit.
The laser power is increased for
F=5 (standard laser power) as
compared with the level used for
scanner input to ensure reproduction of
fine lines narrower than a single pixel.
4-14
COPYRIGHT © 1999 CANON INC.
The developing bias is reduced earlier than the laser
power to prevent fogging.
F value
Lighter
1
3
5
Density
7
9
Darker
Table 4-302 Correction Table for Scanner Input
Table 4-303 Correction Table for PDL Input
Laser power Vdc correction
correction value value
×0.8
-20V
×1.0
×1.2
×1.5
The developing bias is not increased
to prevent fogging.
Laser power
F value
correction value
Lighter
1
2
3
4
5
6
Density
7
8
9
Darker
The bias is corrected to increase
the contrast.
CANON GP605/605V REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Vdc correction VD correction
value value
×0.8
×0.9
×1.0
×1.1
×1.2
×1.3 +10V
×1.4 +20V
×1.5 +30V
×1.5
+40V