Exposure - Epson EPL-N4000 Service Manual

EPSON EPL-N4000/EPL-N4000+

2.4.2 Exposure

The Raster Output Scanner (ROS) generates a beam of laser light.
Image data received from the print controller modulates this beam,
turning it on and off according to image information that is received from
the host computer and software.
Through the use of a series of rotating and stationary mirrors within the
ROS, the beam scans the negative charged drum surface. Whenever
the print controller sends a command to print a black pixel, the laser
switches on long enough to shine onto the drum at a single pixel point.
That point is now discharged and slightly less negative than the
surrounding negative charge. For the sake of simplicity, the less
negative areas are considered "positive". This discharge/no discharge
process creates an invisible, electrostatic image on the surface of the
drum. This image is called a latent image.
The ROS also helps to clean and prepare the drum by scanning the
surface of the drum at the beginning of each individual printer cycle.
This action discharges an residual DC charge that may still remain on
the Drum from the last print cycle.
Rev.B
Sr 1329x
Figure 2-26. Exposure
Chapter 2 Operating Principles
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