Epson EPL-N1600 Service Manual page 48

EPSON EPL-N1600
which is generated by converting the current
flowing through the monitoring Photodiode (PD)
integrated in the LD into an analog output
voltage by means of a resistor.
Scanner Motor Control:
The Polygon Mirror is rotated by the Scanner
Motor (also called ROS Motor). The Scanner
Motor is driven at a constant speed by the
Scanner Motor Drive Circuit using a phase-
locked loop (PLL).
Mirror ASSY: The Mirror Assembly consists of Mirror M1,
Shutter and PWBA SOS.
Mirror M1:
Reflects the laser light beam from the ROS to
the Drum.
PWBA SOS:
Generates a SOS (Start of Scan) signal. The
laser beam hits a photosensor on the PWBA
SOS at the beginning of each scan, and the
PWBA SOS generates a pulse signal (/SOS).
The /SOS signal is used as the reference timing
signal for generating LINE SYNC signal.
Shutter Mirror:
The Mirror Assembly has a Shutter Mirror (A)
covering or exposing the Mirror M1 and lens of
the SOS Sensor. When the Cover Assembly
Exit is open, a projection of the Cover pushes
down the crank arm of the Shutter to raise the
Shutter and expose the Mirror M1 and lens of
the SOS Sensor. When the Cover Assembly
Rev. A
Exit is open or the Mirror Assembly is removed,
the Shutter covers the Mirror M1 and lens of the
SOS Sensor to prevent them from collecting
dust.
Imaging Cartridge The Imaging Cartridge is composed of following
components.
Drum:
An aluminum cylinder with a coating of
photoconductive material on the surface. The
photoconductive coating (layer) holds an
electrical charge placed on the surface while in
darkness, and allows the charge to flow through
into the conductive layer when exposed to laser
light.
BCR (Bias Charge Roll):
Places a uniform electrical charge on the drum
surface, erasing any patterns of decreased
charge remaining from the previous cycle.
Magnet Roll:
Holds toner on the surface in a thin layer and
transports it to the gap between the drum and
the Magnet Roll. Toner is supplied to the
Magnet Roll from the Toner Compartment.
CM Blade (Charging and Metering Blade):
Spreads toner on the Magnet Roll in a thin layer,
and also gives toner a negative charge.
Cleaning Blade:
Scrapes the toner remaining after the Transfer
step off of the Drum surface.
Chapter 2 Operating Principles
49