Epson EPL-N4000 - Exposure

EPSON EPL-N4000/EPL-N4000+ Chapter 2 Operating Principles
Rev.B 70
2.4.2 Exposure
The Raster Output Scanner (ROS)
g
enerates a beam of laser li
g
ht.
Ima
g
e data received from the print controller modulates this beam,
turnin
g
it on and off accordin
g
to ima
g
e information that is received from
the host computer and software.
Throu
g
h the use of a series of rotatin
g
and stationary mirrors within the
ROS, the beam scans the ne
g
ative char
g
ed drum surface. Whenever
the print controller sends a command to print a black pixel, the laser
switches on lon
g
enou
g
h to shine onto the drum at a sin
g
le pixel point.
That point is now dischar
g
ed and sli
g
htly less ne
g
ative than the
surroundin
g
ne
g
ative char
g
e. For the sake of simplicity, the less
ne
g
ative areas are considered "positive". This dischar
g
e/no dischar
g
e
process creates an invisible, electrostatic ima
g
e on the surface of the
drum. This ima
g
e is called a
latent
ima
g
e.
The ROS also helps to clean and prepare the drum by scannin
g
the
surface of the drum at the be
g
innin
g
of each individual printer cycle.
This action dischar
g
es an residual DC char
g
e that may still remain on
the Drum from the last print cycle.
Figure 2-26. Exposure
Sr 1329x