Enlargement/Reduction (Zoom); Changing The Reproduction Ratio In Main Scanning Direction; Changing The Reproduction Ratio In Sub Scanning Direction - Canon iR5000 Service Manual

1.3 Enlargement/Reduction (zoom)

[1] When the copyboard cover is used, the ratio may be between 25% and 400% and the
speed of the scanner is controlled.
[2] When the ADF is used, the ratio may be between 25% and 200% and the speed of
moving the originals is controlled.

1.3.1 Changing the Reproduction Ratio in Main Scanning Direction

For main scanning direction, the original is read at 100% (for both copyboard and ADF);
the size is changed by processing data in the main controller unit.
[1] To reduce, data units are skipped when writing image data to the line memory.
[2] To enlarge, data units are read multiple times when reading image data from the line
memory.

1.3.2 Changing the Reproduction Ratio in Sub Scanning Direction

The reproduction ratio in sub scanning direction is changed by controlling the speed of
the scanner and the speed at which originals are moved. For a reduction between 25% and
49%, however, the main controller unit also functions to change the ratio by processing
data.
[1] To enlarge, the speeds at which the mirror base is moved and the originals are moved
are reduced (i.e., slower than in Direct).
For instance, to enlarge at 200%, the originals are read at 1/2 the speed used for Direct.
[2] To reduce to between 50% and 99%, the speeds at which the mirror base is moved and
the originals are moved are increased (i.e., faster than in Direct).
For instance, to reduce to 50%, the originals are read twice the speed used in Direct.
(speed ratio)
2
1
1/2
1/4
50%
[3] To reduce to between 25% and 49%, the image data read at 50% and 98% is subjected
to skipping (1/2) in the main controller unit.
COPYRIGHT © 2000 CANON INC.
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CHAPTER 2 ORIGINAL EXPOSURE SYSTEM
100% 200%
F02-103-01
2000 2000 2000 2000 CANON iR5000/iR6000 REV.0 JULY 2000
(image ratio)
400%
2-5 R