The GP215/GP200’s image formation process
consists of the following steps as discussed in
sequence:
Step 1 Pre-exposure
Step 2 Primary charging (AC + negative DC)
Step 3 Laser exposure (AC + negative DC bias)
Step 5 Transfer (positive DC)
Step 6 Separation (negative DC)
Step 7 Fixing
Step 8 Drum cleaning
The photosensitive drum has a layer construc-
tion: the outside is a photoconducting layer of
OPC and the inside, conductive aluminum sub-
strate.
Figure 2-103
B. Latent Image Formation
Block
The latent image formation block consists of
three steps, at the end of which negative charges
are left behind in the areas on the drum corre-
sponding to the white areas of the original and
negative charges are removed from the areas on
the drum corresponding to the black areas of the
original.
Such images on the drum created by negative
charges are not visible to the human eye and are
therefore called static images.
Figure 2-104
Photoconductive
Substrate
COPYRIGHT © 1996 CANON INC. CANON GP215/200 REV.0 JULY 1996 PRINTED IN JAPAN (IMPRIME AU JAPON)
2–2
2. COPYING PROCESS
Surface
potential (V)
Time (t)
-500
-1000
Pre-exposure (step 1)
Primary charging (step 2)
Light areas
(dark areas of originals)
Dark areas
(areas not exposured by the laser)
Laser exposure (step 3)