Cmos Sensor Drive - Canon iR2020 Series Service Manual

Chapter 4
- CMOS sensor
- Shading correction
Contact image
sensor (CIS)
Functions of the image processing system are summarized below.
- Reader controller PCB
The reader controller PCB is used to process images on a line-by-line basis. Its major functions are as follows:
1)Analog image processing

- CMOS sensor drive

- CMOS sensor output gain correction and offset correction
- CMOS sensor output A/D conversion
2)Digital image processing
- Shading correction

4.3.6.2 CMOS Sensor Drive

iR2016J / iR2016 / iR2020 / / iR2016i / iR2020i
The CMOS sensor used in this machine is a 1-line linear image sensor consisting of 7488 photocells. After completion of photoelectric conversion in the light-
receiving block, the signals are output to the AP circuit in the reader controller PCB in parallel for each channel (total eight channels) of the CMOS sensor array.
4-12
Reader controller PCB
Analog image processor
CMOS
sensor
Analog
image
processing
Contact image sensor (CIS)
CMOS sensor (1 line)
Analog image signal
IC1
Analog image
processing
A/D
- Gain correction
conversion
- Offset correction
CMOS sensor 4
Light receiving block
T-4-6
Number of lines: 1
Number of pixels: Total 7488 (incl. 7176 effective pixels)
Pixel size: 32 x 46.9 um
Shading correction: Made for each job.
Shading adjustment: Made in the Service mode.
Digital image processor
A/D Shading
processing
conversion
F-4-25
T-4-7
CMOS sensor drive, analog image processing, A/D
conversion, and shading correction
Reader controller PCB
CMOS sensor
Gain
drive control
correction
data
Target
value
RAM
Digital
image
signal
Shading correction
10
F-4-26
CMOS sensor 3
L L H H L H L
F-4-27
Controller
IC2
CMOS sensor
control signal
Serial
communication
I/F
J309
Digital image
signal
8
CMOS sensor 1
output
H H H L
0010-4259