Ricoh A156 - Original Size Detection

4.4 ORIGINAL SIZE DETECTION
The DF detects original width using three original width sensors-1 [A], -2 [B]
and -3 [C]. It also detects the original length using the registration sensor.
The DF CPU counts the feed-in motor’s drive pulses during the on timing of
the registration sensor. Based on this pulse count, the CPU determines the
original length.
The machine detects the original size by the total combination of all four
sensors.
[C]
[A]
[B]
A156/A160/A162 3-8 STM