Digital Image Processing; Outline; Laser Driver Pcb - Canon GP335 Service Manual

III. DIGITAL IMAGE PROCESSING
A. Outline
The digital image processing block processes image signals from the analog image processing
block or from the various extension boards. Figure 4-300 is a block diagram showing the items of
processing.
In the case of making a single copy (a single copy from a signal original), the image data is
converted to 12000-dpi (equivalent) images by smoothing after binary processing, and is sent to the
laser driver PCB (direct copying). In other cases, image data is stored in memory first and then
transferred to the laser driver PCB (memory copying).
Analog image processing block
CCD PCB
Shading correction
Total processing
• Enlargement/reduction
• Shift
• Image composition
enlargement/reduction
• Edge emphasis
• Sharpness
• Nega/posit reversal
Density processing
• Binary processing
• Screen processing
• Resolution conversion
(for fax)
• Smoothing
COPYRIGHT © 1999 CANON INC. CANON 405/335 REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
600x600 dpi

Digital image processing

Direct copying
Image memory
600x600 dpi
600x600 dpi
Compression/
decompression
System motherboard
To extension board
Figure 4-300
CHAPTER 4 IMAGE FORMATION SYSTEM
J717
Image synthesis
(overlay processing)
Fax data
J717
Laser exposure block
J500

laser driver PCB

J500
4-7