Canon imageRUNNER 2545, Service Manual

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Technology > Original Exposure System > Controls > CCD
Technology > Original Exposure System > Controls > CCD
1) Forward movement when scanning an image
CCD operation is controlled by the following sensors when scanning the image.
Start position
position
Acceleration
Original
leading edge
Normal speed
Original
trailing edge
Deceleration
Stop
Shift
speed
Shift distance
[1] [2] [3] [4]
[1]Acceleration area: Accelerates until a speed suited to the selected mode is reached
[2]Run-up speed area: Run-up margin to ensure a stable speed.
[3]Image reading area: Reads an image at a specific speed.
[4]Deceleration area: Decelerates and stops promptly once the image end is reached.
2) Backward movement after scanning an image
After scanning an image, CCD moves backward to CCD shading position at a specific
speed (249.5 mm/sec).
F-2-11
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CCD
● Overview
The machine uses the CCD to expose and read an image and the image is read on a line-by-
line basis.
CCD features 4 lines (R, G, B, B/W) and B/W line is used in B/W copy and R, G, B lines are
used at color scan.
CCD overview
1. Integrated scanning configuration; CCD, lens, light source and mirror are integrated.
2. CCD elemental size: 4.7 μm
3. Lens diameter: 18mm dia
4. Light source: LED
5. Effective number of pixel: 7500 pix x 3 color lines, 7500 pix x 1 B/W line
[Optical path from LED]
The light generated from LED is reflected by an original and by the 5 mirrors. And then it is
irradiated to the CCD through the lens.