Epson EPL-9000, Service Manual

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EPL-9000
Service Manual Operating Principles
2.1.1.1 Drum Charge
Drum charge is the process of charging static electricity to the (Organic Photo Conductor)
drum before laser exposure. The charge wire discharge to the drum surface potential of the
drum even. The charge screen between the charge wire and the drum, which is
connected to the ground through the diode, limits the discharge to the drum to
maintain the drum surface potential at the specified level (-310
Charge Screen
1
Figure 2-4. Drum Charge
2.1.1.2 Laser Exposure
Laser exposure is the process of creating an invisible static electricity image on the drum by
laser beams emitted from the ROS (Raster Output Scanner) Assembly. The polygon mirror is
rotated by the polygon motor (scanner motor). This is
a
six-sided mirror which rotates in the
clockwise direction to produce a laser light scan (one side of the mirror produces one scan). The
SOS (Start Of Scan) sensor detects the laser rays from the SOS mirror and outputs SOS signals in
order to make the starting position of each line of the image uniform.
Laser emission
/ ’ - l
PC Drum
Invisible
electricity image
I
Scanner Assembly
Figure 2-5. Laser Exposure
Rev.
2-3