Specifications

EPSON EPL-N1600 Chapter 2 Operating Principles
Rev. A 48
XEROGRAPHIC MODULES
ROS ASSY: The ROS (Raster Output Scanner) Assembly
scans a laser beam on the drum surface. The
ROS Assembly consists of two major
components: PWBA LD and Scanner Assembly.
Basic Operation:
The Laser Diode (LD) of the PWBA LD emits
laser li
g
ht. The LD is switched on and off
accordin
g
to the print ima
g
e si
g
nal durin
g
printin
g
. The power of the laser li
g
ht is
monitored by the monitor circuit and controlled
to be a constant power. The laser li
g
ht from the
LD is shaped and conver
g
ed into a very thin
beam by means of a slit and a Cylinder Lens,
and directed to a Poly
g
on Mirror. The Poly
g
on
Mirror has six facets and is rotated at a constant
speed by the Scanner Motor. These facets
reflect the laser beam in turn as the Poly
g
on
Mirror rotates. The laser beam reflected by the
Poly
g
on Mirror passes throu
g
h a Correction
Lens L1 and is reflected by a Mirror M1 onto the
drum surface, movin
g
from one end of the Drum
to the other. The laser beam is thus scanned
one line by each facet of the Poly
g
on Mirror.
LD Output Power Control:
The drive current of the LD is switched on and
off by the Current Switchin
g
Circuit in the LDD
(Laser Diode Driver) accordin
g
to the print
ima
g
e si
g
nal (/PDATA) from the en
g
ine control
circuit. The LD drive current while the LD is on is
precisely determined by the two DC volta
g
e
si
g
nals (VLI and VL2) from HMCU. The laser
power is monitored usin
g
a monitor si
g
nal (MO),