Density Processing - Canon imageRUNNER 330 Service Manual

CHAPTER 4 IMAGE FORMATION SYSTEM
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:
Direct Copying
Image density/image mode set
Copy Start key ON
Original scan
Multiple-value data

Density processing

(density correction curve)
Multiple-value data
Binary processing
(for image output)
Binary data
Laser exposure
Development
Output end
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).
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COPYRIGHT © 1999 CANON INC. CANON imageRUNNER 400/330 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
Memory Copying
Copy Start key ON
Read image density/read
image mode set
Copy Start key ON
Original scan
Multiple-value
data
Density processing
(density correction curve)
Multiple-value data
Binary processing
(from image memory read)
Binary data
Image memory
Binary data
Laser exposure
Image
density fine a
djustment
Development
Output end
Figure 4-305
Processing by density
correction curve
Laser output and
developing bias varied