Duplex Print Magnification Correction; Execution Timing; Control Description; Main Scanning Direction - Canon imageRUNNER ADVANCE 8105 Series Service Manual

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Technology > Laser Exposure System > Controls > Duplex print magnification correction
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Duplex print magnification correction

When the paper passes through the fixing area after the image was created on the 1st side of
the 2-sided print, the paper temporarily gets shrunk due to the heat. Then, creating the image
on the 2nd side causes the 2nd side image extended, which makes the 2nd side image larger
than the 1st side image when the paper size returns to the original size after the paper is
delivered outside the machine.
<Execution timing>
When the image on the 2nd side of 2-sided print is created
<Control description>
When the 2nd side is printed, the following controls are executed with consideration of paper'
s shrinkage level.

Main scanning direction:

The image in horizontal scanning direction is reduced by skipping the image data.
Sub scanning direction:
The image is reduced by increasing rotating speed of the Polygon Motor.
Increasing rotating speed of the Polygon Motor causes an increase of magnification ratio in
horizontal scanning direction, and equally effects as skipping of image data.
2 Technology > Laser Exposure System > Controls > Duplex print magnification correction
Horizontal scanning
Vertical
scanning
<Polygon Motor Swing Speed>
<Constant Speed>
L
L > L'
> '
2-41
<Laser Lighting>
Without
Correction
With
Correction
<Speed Up>
L'
'
:Exposure
F-2-56 F-2-56
2-41