Ricoh PRIPORT VT 2000 Series Service Manual page 61

28 February '91
2.6 REDUCTION PROCESSING:
A/D Converter
BAD 1
BAD 2
BAD 3
BAD 4
24V
Original
Transport
M
Motor
Drive
Circuit
CN-NO Signal
Reduction 0
105-19
(Magnification 0)
Reduction 1
105-20
(Magnification 1)
(105-21)
(Magnification 2)
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.
2.6.1 Main Scanning Reduction:
Reduction Mode
100 %
93 %
82 % (A4 version)
75 % (LT version)
71 % (A4 version)
64 % (LT version)
When the reduction command is sent from the main board, the timing signal
generator sends the thinning timing control signal to the reduction
4 bit
Image
Data
CN403-17 ORF0 A
CN403-18 ORF0 B
CN403-19 ORF0 C
CN403-20 ORF0 D
CN403-21 ORF0 E
I/O
I
I
(I)
Discarded Pixels
0 Pixels
1/14 Pixels
3/11 Pixels
1/4 Pixels
2/7 Pixels
5/14 Pixels
Image Processing PCB
Image Data
Reduction
Processing
Discard Timing
Drive
Pulse
Generator
( ): VT2300/VT2500
FROM 100 %
Main PCB H
Main PCB H
(Main
(H)
PCB)
(
Remaining Pixels
13/14 Pixels (0.929)
9/11 Pixels (0.818)
3/4 Pixels (0.75)
5/7 Pixels (0.714)
9/14 Pixels (0.642)
2-34
Image
Processing
Timing Signal
Generator
CN
105-19
CN
105-20
(CN
105-21)
82 %
93 %
[75%]
L H
H L
(H) (H)
): VT2300/VT2500
All Pixels
Main PCB
Reduction 0
(Mag. 0)
Reduction 1
(Mag. 1)
(Mag. 2)
71 %
[64%]
L
L
(H)