Canon GP405, Service Manual

Page: 98 / 682

CHAPTER 4 IMAGE FORMATION SYSTEM
4-12
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
D. Density Processing
1. Outline
Density processing takes place differently between direct copying and memory copying; i.e.,
when making one copy of one original and when making multiple copies of one original. The flow
of processing will be as follows:
Figure 4-305
When reading an image, digital processing may take place using a density correction curve for
handling multiple-value data; however, since binary data is used when generating output in
memory copying (not having density information), the laser intensity and the developing bias are
varied for the reproduction of density (as if in analog mode).
Original scan
Output end
Copy Start key ON
Read image density/read
image mode set
Density processing
(density correction curve)
Multiple-value
data
Multiple-value data
Binary data
Copy Start key ON
Laser exposure
Development
Binary processing
(from image memory read)
Binary data
Image memory
Processing by density
correction curve
Laser output and
developing bias varied
Image
density fine a
djustment
Memory Copying
Original scan
Output end
Image density/image mode set
Density processing
(density correction curve)
Multiple-value data
Multiple-value data
Copy Start key ON
Laser exposure
Development
Binary processing
(for image output)
Binary data
Direct Copying