Panasonic UF-890 Service Manual page 218

6.1.2 Receive Mechanism
The Receive Mechanism consists of the Laser Unit (LSU), OPC (Organic Photo Conductor) Drum, and
various other parts which ensure the normal feeding of recording paper. These components and their
functions are as follows:
Paper Feed Units No.1 and 2
Paper Feeder Unit No.2 is optional.
Cassette Paper Detection operation
The NP Actuators attached to the Paper Feed Blocks No.1 and 2 determine if there is paper in the
cassette.The paper in the cassette lifts up the NP Actuator, allowing the light from the LED to actuate the
phototransistor. The output signal level (nPCHK1 or nPCHK2) is shown in the table below.
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