Oki OKIOFFICE44 Service Manual page 269

A3.1.5 R44 Circuit Diagram
1. Block diagram
The circuit diagram consists of the following functions:
• IC6 (A/D converter)
• 30 V/24 V conversion circuit
• Connector CN5 that provides an interface between R44 board and CIS (contact image
sensor).
Figure A3.1.5 shows the related signals and block diagram of CIS.
2. Function
One-line picture data is read in the sequence from the scanning unit (CIS) as SIG signal
(analog data) to A/D converter (analog/digital converter) of IC6. After conversion from analog
data to 6-bit digital signal (SDATA0 - SDATA5) under the control of IC6, this picture data is sent
to IOGA3 (input/output gate array). Here, the picture data undergoes various kinds of picture
processings.
Sensor interface signal output from IOGA3
• LEDON : LED on/off control signal
• SNSCLK : Scanning sensor drive clock (714.286 kHz)
• MISP
• ADCLK : Sampling clock for A/D converter (714.286 kHz)
IC2
IOGA
SDATA0 - SDATA5
IC6
A/D converter
30 V/24 V conversion
30V
circuit
Figure A3.1.5 Related Signals and Block Diagram of CIS (contact image sensor)
Board Descriptions
: Scanning synchronous signal (5 msec)
R44
CN5
Transistor
VLED
LEDON
TR9/TR10
GLED
MISP
DCK (714.286 kHz)
SIG
+5 V
-8 V
0 VA
24 V
A - 27
CIS (contact image sensor)
VLED (+24V)
10
9
GLED
6 MISP
Shift register & analog switches
8 DCK
1
SIG
3
+5 V
4
-8 V
2, 5, 7
0 VA
OKIOFFICE 44 Serv. Man., P/N 59276801
LEDs array
Rod lens array
sensor
1728 bit (216 mm)
Amplifier