Original Size Detection; Change Of Magnification Ratio; Color Displacement Correction In Vertical Scanning Direction - Canon imageRUNNER ADVANCE C3325 Series Service Manual

2
Technical Explanation > Document Exposure > Controls > Original Size Detection
● Change of Magnification Ratio
The scanner performs reading at 600 dpi or 300 dpi. For the color mode, only COLOR mode
is used; the scanner does not perform reading in B&W mode scanning regardless of the color
mode selected in the Control Panel.
When configured to read in black and white, the controller converts the mode to black and
white to perform processing.
Copyboard/ADF Resolution (dpi)
600
300
Copyboard
600
300
600
300
ADF
600
300
● Color displacement correction in vertical scanning direction
Color displacement correction control in vertical scanning direction is a processing to correct
the displacement in RGB by shifting pixels in the vertical direction (up to 1 pixel) to align
GREEN with RED and BLUE images when RGB cannot be read such that they are accurately
overlapped at color scanning.
Example) Scanned image of black line when RED is shifted upwards and BLUE is shifted
downwards compared to GREEN
Color offset in
sub scanning
R-G
1 line
Color offset in
sub scanning
G-B
There are two types of color displacement correction values as shown below: The correction
value is adjusted in advance before shipping and is saved in service mode. (In COPIER >
ADJUST > CCD)
When a job is started, color displacement correction processing is performed based on the
saved color displacement correction values.
Reader Scan
• 100-RG
• 100-GB
2 Technical Explanation > Document Exposure > Controls > Original Size Detection
Color in which the scanner
Color/B&W
performs reading
Color
Color
B&W
Color
Color
B&W
Before correction
After correction
F-2-10
T-2-5

■ Original Size Detection

● Overview
This machine determines the size of an original by the combination of the measurement
results of the reflected light at particular points of the Reflection Sensor and Reading Sensor.
Furthermore, two points are measured for each size to perform accurate detection even if the
original is moved when the ADF is closed.
• Horizontal scanning direction: Reading Sensor (15-point measurement)
• Vertical scanning direction: Reflection Photo Sensor (1 point for AB configuration, 1 point
for inch configuration)
The original size is determined using the following procedure:
1) Search of external light (horizontal scanning direction only)
The sensor level at each detection position in the horizontal scanning direction is measured
while the LED is OFF.
T-2-4
2) Detection of output level of each sensor
The LED of the Reading Sensor Unit is turned ON to measure the sensor level at each
detection position in the horizontal scanning direction.
Furthermore, the Reflection Photo Sensor LED for the vertical scanning direction is turned
ON to measure the sensor output.
The original size is determined by the combination of these outputs.
The detectable sizes differ depending on the country. The country setting can be changed in
service mode.
* When KSIZE-SW is set for configurations other than inch configuration (including GLOBAL),
the original is detected as AB/K configuration.
SENS-CNF
0
0
1
-
-
The sensor needs to be changed when switching the detection configuration between AB and
Inch.
MODEL-SZ2 KSIZE-SW
0 0
0 1
0 -
1 1
1 0
2-8
Detection configuration
AB
AB/K
INCH
AB/K
GLOBAL
T-2-6
2-8