Magnification Ratio; Original Size Detection - Canon imageRUNNER ADVANCE C3500 III Series Service Manual

The Reading Sensor has 4 lines (R, G, B, and B/W). At 600 dpi B&W reading, 1 line (B/W) is used. At color reading, 3 lines (R,
G, and B) are used.
Related error codes
Light intensity error:
• E301 - 0001: Light intensity is below the reference level at paper front shading.
Shading error:
• E302 - 0001: Error in paper front white shading
• E302 - 0002: Error in paper front black shading

Magnification Ratio

■ Changing the Magnification Ratio in Horizontal Scanning Direction
When using the reading mode of the reader / When using the ADF
Reading in the horizontal scanning direction is performed at 100% size. Changes to the magnification ratio are processed by the
Main Controller PCB.
■ Changing the Magnification Ratio in Vertical Scanning Direction
As the magnification change in vertical scanning direction, the following operation is performed according to the original reading
method and difference in magnification.
Magnification change when using the reading mode of the reader
Data processing in the Main Controller PCB is performed according to the magnification.
Example: In the case of reducing the magnification to 25%, the original is read at 260 mm/sec, and is reduced to 25% in the Main
Controller PCB (1/4 decimation).
Example: In the case of magnification 100 %, the original is read at 260 mm/sec.
Operation description
Original reading speed (mm/sec)
Digital magnification processing
in the Main Controller PCB (%)

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. Measurement is performed for each size to perform accurate detection even
if an original is moved when the ADF is closed.
• Horizontal scanning direction: Reading Sensor
• Vertical scanning direction: Reflection Photosensor
The following procedure is used to determine the size of the original.
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.
2. Detection of output level of each sensor
The LED of the Reading Sensor Unit is turned ON, and the sensor level at each detection position in the horizontal scanning
direction is measured.
Then, the Reflection Photosensor LED for the vertical scanning direction is turned ON, and the sensor output is measured.
The size of the original is determined by the combination of these outputs.
25 % to 50 %
260
25 to 50
40
Magnification
50.1 % to 199.9 %
260
50.1 to 199.9
2. Technology
200 % to 400 %
260
100 to 200