Oce 3121, Technical & Service Manual

Page: 285 / 908

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ed.1 08 Image processing 509
The image of a document may be shifted by combining shifts in the forward
scanning direction and shifts in the reverse scanning directions.
1 Corner Shift
The co-ordinates (X1, Y1) of the corner of a specific area is moved to any of
the four corners of the copy.
2
Centre Shift
The co-ordinates (Xm, Ym) are computed from the size of the area to be shift-
ed and the size of the copy, so that the margins at the top and the bottom and
the margins at the left and the right will be identical; the area will be moved to
X1 and Y1.
Note: Xm= (Xmax–(X2–X1))/2, Ym= (Ymax–(Y2–Y1))/2
3
Free Shift
The co-ordinates (X1, Y1) of a specific area is moved to a specific point (Xp,
Yp).
a b c a b c a b c
a b c
a b c
<Original>
Main scanning
direction
Sub
scanning
direction
<Copy>
Shift
in sub scannig direction
<Copy>
Principle : When data for a single scanning line is
read from line memory, reading is started
with a midway pixel or the timing at which
the data of the first pixel is read is delayed,
thereby shifting pixel position.
Principle :
The position or the timing
at which the original
illuminating system is started is
varied to shift the position of
the image.
Shaft in main scanning direction <Document>
The forward scanning
--> direction
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<Copy>
<Copy>
Shift in the reverse scanning direction
Principle
Principle
When data for a single scanning line is read
from line memory, reading starts with a midway
pixel. Or, the timing at which the data of the
first pixel is read is delayed, thereby shifting
the pixel
The position is varied, or the
timing at which the document
illuminating system is started
is varied, to shift the position
of the image.
a b c
a b c
a b c
Shifting in Main Scanning Direction
Main scanning derection
Not read
<Memory>
Reading starts
with this pixel.
a b c
a b c
a b c
Main scanning direction
Reading starts with this pixel.
Not read.
Shifting in the forward scanning
direction
--> The forward scanning
The reading starts with this pixel
The reading starts with this pixel
Not read
Not read
<memory>