Toshiba E-STUDIO190F Service Manual page 189

6.3.4.3. Collimator Lens
The Collimator Lens converts light from the Laser Diode to parallel light. This aids in scanning and provides
better convergence to a dot.
6.3.4.4. Polygon Scanner
The Polygon Scanner consists of a 6-sided Mirror directly driven by a brushless DC Motor at a rate
20,078.74 rpm. The laser beam is reflected across the OPC Drum by the mirror faces and produces the
scan. One mirror face is equal to one main scan. This unit features stable line scanning speed, precision
mirror surface reflection angle, reflect-free surfaces, and instant start.
6.3.4.5. Cylindrical Lens and
Each of the Polygon Mirror surfaces has a slight imperfection. This prevents the beam from scanning the
OPC Drum surface at the constant interval in the sub-scan direction. The Cylindrical Lens and
are used for correcting this uneven laser scanning.
6.3.4.6. Lens
This lens ensures that the beam scans across the surface of the OPC Drum at a constant rate. The beam is
refracted to parallel light as it passes through the lens to ensure that the dots at the edge of the drum and at
the center of the drum are equally spaced. This lens also provides a set focal length for laser beam.
Focusing Light Spot Size
6.3.4.7. Timing Sensor
This sensor detects the laser beam and determines the start timing for scanning. A pin photodiode is used
as the Timing Sensor.
Polygon Scanner Specifications
Item
Mirror
Revolution
Lens
Item
Scanning Width
Specification
6
20,078.74
Specifications
Specification
207.43
80 x 90
189
faces
rpm
Lens
mm
µm