2-8 Phaser 4500/4510 Service Manual
Theory of Operation
Registration
sensor
Mechanically
actuated photo
sensor
Detects the paper as it
reaches the registration
rollers.
Page 2-10
Page 2-16
Toner sensor Magnetic sensor Detects the presence of
toner in the print cartridge.
Page 2-16
Exit sensor Mechanically
actuated photo
sensor
Detects paper as it leaves
the fuser.
Page 2-22
Output tray full
sensor
Mechanically
actuated photo
sensor
Detects when the standard
output tray is full.
Page 2-27
Temperature
sensor
Soft Touch Sensor Two of these monitor the
temperature of the Heat
roller.
Page 2-22
Rear cover
switch
Microswitch Interrupts +24 V to the main
motor when the rear exit
cover is open; in series with
24 V interlock.
Page 2-30
24 V interlock Microswitch Interrupts +24 V to the main
motor when the top cover is
open; in series with rear
cover switch.
Page 2-30
Top cover switch
(P4500 only)
Microswitch Interrupts INTERLOCK BEF
to indicate the top cover is
open.
Page 2-30
Laser interlock
(P4500 only)
Microswitch Interrupts +5 V to laser
diode; in series with 5 V
interlock switch.
Page 2-30
5 V interlock Microswitch Interrupts +5 V to laser
diode. In series with laser
interlock.
Page 2-30
Start of scan
sensor
Photo Detects the laser beam at the
start of a scan.
Page 2-20
Fuser
thermostat(s)
Thermostatic
switche(s)
Interrupt AC power to the
fuser heater in overtemp
condition; P4500: two
switches in series; P4510:
single switch.
Page 2-22
Stacker rear
cover switch
Microswitch Signals the HVPS/engine
logic board that the stacker
rear cover is open.
Page 2-38
Stacker sensor Mechanically
actuated photo
sensor
Senses the presence of
paper in the stacker.
Page 2-38
List of Sensors and interlocks
Name Type Function Reference