Ricoh C211 Service Manual page 429

7. Reduction Processing: SS950
Reduction in the main scanning direction is performed by systematically discarding the
pixels and the reduction in the sub-scanning direction is performed by changing the
transportation speed of the original.
7-1. Main Scanning Reduction: SS950
[
L
Reduction Mode Discarded Pixels
Remaining Pixels
100
Yo
O
Pixels
All Pixels
9370
1/1
4 Pixels
13/14 Pixels (0.929)
82% (220/240V) 2/11 Pixels 9/1 1 Pixels (0.818)
75% (120V)
1/4 Pixels 3/4 Pixels (0.75)
71 % (220/240V) 2/7 Pixels
5/7 Pixels (0.714)
64% (120V) 5/1 4 Pixels
9/1 4 Pixels (0.642)
4
When the reduction command is sent from the main board, the timing signal generator
sends the thinning timing control signal to the reduction processing circuit. Some of the
4-bit image data from the A/D converter is discarded according to the thinning timing
control signal.
Examples
During the 82V0 reduction mode, 9 out of 11 pixels are used;
2 pixels are discarded each
cycle.
]o 12345678 9
10 IO.1
Before thinning
I
/
•.
9 pixels
01
234
5~#A 2 3
After thinning
I
(3rd and 8th pixels are removed.)
During the 93% reduction
mode, 13 out of 14
pixels are used; 1 pixel is discarded each
cycle.
Before thinning
After thinning
<
14 pixels
w
01
2 3 4 5 6 7 8 9 10 11 12 13
I
L 6th
pixels
is removed.
*
13 pixels
" /"
01,2345G 789101112
()
I
I I I
I I I I
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