Ccd - Canon imageRUNNER 2545 Series Service Manual

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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
Original
position
leading edge
Acceleration
Shift
speed
[1] [2]
Shift distance
[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).
2 Technology > Original Exposure System > Controls > CCD
Original
trailing edge
Stop
Deceleration
Normal speed
[3] [4]
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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.
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