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AR-651/810 SCANNING SECTION 6 - 14
The reflection type photosensor is comprised of an infrared light emitting diode and a phototransistor. It
uses the pulse modulation to detect an original.
The light emitting diode is driven by a pulse having a 130-µsec cycle and an 8-µsec ON time. When the
phototransistor receives the same signal as this pulse, it is determined that there is an original. The
pulse modulation is performed inside the reflection type phototransistor.
About reflection type photosensor
130µsec
LED
8µsec
Original
Phototransistor
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