Ricoh B234 Service Manual page 798

SCANNING
The original size data is taken by the main CPU when the APS start sensor is
activated. This is when the ADF is positioned about 12 cm above the exposure
glass. At this time, only the sensors underneath the original receive the reflected
light and switch on. The other sensors are off. The main CPU recognizes the
original size from the on/off signals from the five sensors.
If the copy is made with the ADF open (book mode), the main CPU decides the
original size from the sensor outputs when the [Start] key is pressed.
This original size detection method eliminates the necessity for a pre-scan and
increases the machine productivity.
The tables on the next pages show the outputs of the sensors for each original
size.
5
4
A5
B5
16-K
1
A5 A4
LT Fool LG
2
10"x14"
B5 B4
16-K
8-Kai
LT DLT
3
A4 A3
B234D931.WMF
B234/B235/B236/D101/D102/D103 6-36 SM