Printronix L1024, Maintenance Manual

Page: 107 / 372

7–11 Chapter 7 – Fuser Subsystem
7.2.2 Electrical
The electrical portion of the fuser has four main sections:
S
A halogen lamp for heating the Fuser. In series with the lamp is a Thermal Breaker to
switch off power to the lamp if there is a problem with the heater control circuit.
S
A sensor board mounted to the Fuser Base Assembly. This sensor board has six optical
sensors associated with it that monitor the Fuser when up, the Fuser when down, the
Paper Handling Lever position, the Speed Control Lever position, and entry and exit paper
jam sensors.
S
A thermistor sensor mounted to the frame of the Fuser Assembly that monitors the heat
of the Fuser Roller.
S
Two fans mounted in the Fuser Frame that cool the ends of the Pressure Roller.
Details about specific Units:
Fuser Fans. These fans cool the outer edges of the Pressure Roller, which is especially useful during
narrow-forms printing.
Fuser Cam Clutch. This is a clutch that causes the Fuser Roller Cam Shaft to rotate in order to open or
close the Fuser and move the Paper Handling Lever and the Speed Control Lever.
Fuser Sensor Board. This board has 4 optical sensors: 2 for positioning the Speed Control Paper Guide,
and 2 for positioning the Fuser Roller Cam. The Fuser Sensor Board is the interface between the Engine
Controller and the Fuser.
Fuser Stepper Motor. This motor drives the Fuser forward. Additionally, if the Fuser Cam Clutch is on, this
motor drives the Fuser Roller Cam Shaft.
Heater Lamp. The Heater Lamp is located in the center of the Fuser Roller and heats the Fuser Roller.
Thermistor. This is a temperature sensor that is in contact with the Fuser Roller. It is used in conjunction
with the heater circuitry to keep the Fuser Roller at the correct temperature.
Thermal breaker. This is a heat-activated switch in series with the lamp heater circuitry. It functions as a
power shutoff when it reaches 155
°
C.