Xerox Phaser 6130 Service Manual page 76

Theory of Operation
2-26
Laser Diode Board
The Laser Diode Board consists of four laser diodes (LDs) corresponding
to C, M, Y, and K. Each LD converts the electric signals of incoming image
data into laser waves. In order to stabilize the laser light quantity during
formation of an electrostatic latent image, the LD Board monitors the
intensity of the laser beam to adjust it to the appropriate level. This
process is called Auto Power Control (APC).
Scanner
The Scanner consists of a Scanner Motor that rotates at a constant speed
and a Polygon Mirror that is mounted on the Motor Shaft. The laser light
output from the LD is directed onto the Polygon Mirror by the Mirror. The
Polygon Mirror, provided with six reflecting mirror faces, changes the
reflection angle of the laser light as it rotates, thereby allowing the laser
light to scan the drum along its axial direction. Scanning is performed
using one reflecting mirror face for each line.
Start of Scan (SOS) Board
The SOS Sensor on the SOS Board converts incoming laser beam, upon
detection, to an electric signal as reference for starting scanning, and
transmits this signal to the MCU Board. The SOS sensor signals are used
to synchronize the starting point of the laser beam scanning with the
starting point of the image writing.
Lenses
The laser light reflected from the Polygon Mirror reaches the drum surface
via the Lenses, Mirror, and Window. The Lenses correct aberration.
Mirror
The Mirror directs the laser beam and secures an optical path.
Window
The window prevents debris from entering the Laser Unit.
Phaser 6130 Color Laser Printer Service Manual