Photosensor - Ricoh FT7770 Service Manual

2. Photosensors
The following sensors are reflective photosensors that are used to detect
paper moving through the copier.
Sensor
Duplex Paper Feed
Lower Paper Feed
Pick-off
Registration
Upper Paper Feed S-5
Pre-registration Sensor S-26
When the copy paper reaches the sensor, light from the LED reflects from
the paper and activates the phototransistor.
HIGH signal to pin 6 of the comparator (IC). The comparator then applies
a LOW signal to the main board.
NOTE: The image density sensor and oil end sensor are also photosensors
but have different circuits.
cuit description.
Symbol
Connector
S-15 CN202-B6
S-11 CN202-A6
S-17 CN202-A20
S-18 CN202-B8
CN202-B5
CN203-A8
See their respective sections for a cir-
2-105
The phototransistor applies a
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April, '89