Canon 1750, Service Manual

Page: 46 / 358

2
2
2-18
2-18
Technical Explanation > Original Exposure and Feed System > Controls > Image Processing
Technical Explanation > Original Exposure and Feed System > Controls > Image Processing
■
Dust Detection Correction Control
Whenever the original from the ADF is read, presence or absence of duct is detected at the
original read position determined in the dust detection preventive process. If presence of dust
is detected, the image correction process is performed to prevent dust from appearing in the
output image.
Main power
switch ON
Dust detection
correction control
Dust detection
correction control
STBY WMUPR
Start key ON
1st
SCAN
2nd
SCAN
Dust detection
correction control
F-2-29
■
Image Processing
● Overview
Major specifications and functions of the image processing system are as follows:
• Original reading sensor array Number of lines: 1
Number of pixels: Total 5148 (incl. 5104 effective pixels)
• Shading correction Shading correction: Performed for each job.
Shading adjustment: Performed in the Service mode.
Reader controller PCB
Original reading
sensor
Analog image processor Digital image processor
Shading
processing
A/D
conversion
Contact image
sensor (CIS)
Main
controller
PCB
Analog
image
processing
About image processing, the function of the reader controller PCB is as follows:
• Original reading sensor drive
• Original reading sensor output gain correction and offset correction
• Original reading sensor output A/D conversion
• Shading correction
• LED intensity adjustment
F-2-30