Scanning System - Brother HL-2400C Service Manual

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Scanning System

This printer employs a semiconductor laser diode as a light source. This laser diode is
switched according to the transmitted image data (video signal).
The generated laser light scans over the OPC belt through a polygon mirror and lens, by
which method electrostatic latent images will be formed on the OPC belt.
(1) Structure of the Scanning System (Refer to Fig.4-24.)
The scanner unit is located as shown in Fig.4-8.
The scanner unit consists of the following parts;
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Laser Unit: Light emitting source incorporating a laser diode.
Cylinder Lens: Condenser for the laser beam.
Polygon Mirror: Hexahedral mirror for scanning the laser beam.
θ
Focus lens for the laser beam.
F- Lens:
Scanner Motor: Motor to rotate the polygon mirror.
Mirror: Reflecting mirror for the laser beam path.
LDC: Laser diode control circuit.
PD: Beam detector.
BTD Mirror: Beam timing detector mirror to guide the laser beam
to the PD sensor.
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Fig.4-24
IV-21
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