Ricoh LDD250, Service Manual

Page: 339 / 459

IMAGE PROCESSING
SM 6-17 C262/C265
Detailed
Des
cription
s
6.3 IMAGE PROCESSING
6.3.1 OVERVIEW
The CCD converts the light reflected from the original into an analog signal. The
CCD line has 7,450 pixels and the resolution is 600 dpi (23.6 lines/mm).
After the above process, the A/D converter built into the SBU transforms the analog
signals into 8-bit signals. This assigns a value to each pixel from a scale of 256
grades. Then, the digitized image data goes to the ECU board.
The image data then goes to the ECU board, which carries out the following
processes on the image data:
1. Auto shading
2. Filtering (MTF, Adaptation Filter and smoothing)
3. Main scan Magnification/Reduction
4. Centering
5. Binary processing
6. Erase Shadow
7. Memory functions
SBU
Thermal
Head
IPU
ECU
Memory
CC
D
Memory
ACU
C262D007.WMF