Xerox Phaser 7400

2-16 Phaser 7400 Color Printer Service Manual
Microswitches
Microswitches are used primarily as paper size sensors and cover or door interlocks.
They are in a normally open state, and close when actuated. A bank of microswitches
is used to detect paper size in the universal trays.
Thermistors
Thermistors have a known value of resistance at a certain temperature. Used primarily
in the Fuser for temperature sensing.
Hall-Effect
Hall-Effect sensors detect the magnetic properties of the actuator. Hall-Effect sensors
are used to monitor activity of the Waste Toner Recovery system and Transfer Unit
belt. Use a magnetic source to actuate these sensors during testing.
List of Sensor and Interlock Types
Name Type Function
Level Sensor Photo-receptive Detects paper stack height in Trays 2~6.
No Paper Photo-receptive Detects no paper condition in all trays.
Paper Size Microswitch array Detects the tray and the paper size.
Registration Photo-receptive Detects paper at the registration rollers.
Color Registration Photo-reflective Monitors color registration.
Feed-Out Photo-receptive Detects paper leaving the feeder.
Fuser Exit Photo-receptive Detects paper as it leaves the Fuser.
Stack Full Photo-receptive Detects when the output tray is full.
Temperature Thermistor Monitor Fuser roller temperatures.
Door Interlocks Microswitch Interrupts +24 V to the Motors.
Low Toner photo-reflective Detects toner in the Imaging Units.
Fuser Thermostats Thermostatic switches Interrupts AC power to the Fuser.
Offset Home Photo-receptive Detects Offset carriage position.
Temp/Humidity Integrated circuit Monitors the printer’s environment.
Waste Toner Hall-effect Monitors waste augers and transfer belt.
CRUM antenna RFID code reader Communicates with the CRUMs.