Canon NP6012 Service Manual page 41

~~ ______—— SSS STO (9) ING PROCESS ag
During copying, the toner is attracted to
the photosensitive drum by the photosensi-
tive drum surface potential and the develop-
ment bias (positive component), thus turning
the static latent image into a visible image.
Any excess toner is repelled by the photo-
sensitive drum by the photosensitive drum
surface potential and the developing bias
(negative component).
A DC bias affects copy density and the
degree of fogging; the higher, i.¢., closer to 0
V, it is, the darker the images will be—how-
ever, with an increased tendency toward fog-
ging.
G. Transfer (step 5)
Figure 2-110
A negative voltage is applied to the back
of copy paper to transfer toner from the sur-
face of the transfer drum to the copy paper.
The copier uses a roller transfer system,
which has the following advantages when
compared with the conventional corona
transfer system:
* Generates virtually no ozone.
* Provides good feeding, since copy
paper is retained by both the transfer
charging roiler and the photosensitive
drum.
COPYRIGHT © 1995 CANONINC.
Reference:
Toner may collect on the transfer roiler if
the image on the photosensitive drum
fails to transfer to the copy paper
because of a jam or the like.
The copier turns the transfer voltage to
positive during initial rotation, while the
scanner is moving in reverse, and during
post rotation to return the positively
charged toner adhering to the transfer
roller to the photosensitive drum.
Were a ys
Transfer roller
Figure 2-111
CANON NP6O12/NP6012F /NP6212 REV.1 SEPT. 1995 PRINTED IN JAPAN (IMPRIME AU JAPON} 2-5