Xerox Phaser 6115 MFP, Service Manual

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Phaser 6115MFP Multifunction Product Service Manual 2-57
Theory of Operation
Tray Detect Switch
The Tray Detect Switch signals the presence of a tray in the feeder. The switch
is On when the tray is fully-inserted in the feeder.
Sensors
The printer contains sensors of various types that perform a variety of
functions. One group of sensors track the progress of the paper along the
paper path, and detects if a paper jam occurs. Other sensors detect the
presence of the Toner Cartridges, stop printer activity if a door is open
(interlock), detect the presence and size of media in the trays, and monitor the
fusing temperature.
The types of sensors used vary with function. In general, there are three types
in use:
Photo Sensors
Two types of photo sensors are used, photo-reflective and photo-receptive.
Photo-reflective sensors use light reflected back from an object to detect its
presence. Photo-receptive sensors use an actuator or the object itself to block
the light path to detect an object or condition.
Photo-reflective sensors have the light emitter and light receiver aligned on a
single surface. Output of the photo-receptor is High (> +4.5 V) when light is
being reflected back and Low (< +.3 V) when it isn’t. Photo-receptive sensors
consist of a LED in one arm of a U-shaped holder, and a photo-transistor in
the other arm. When the sensing area is vacant, nothing is between the arms
of the sensor, light falls on the photo-receptor sending the signal High. If the
light is interrupted, the photo-transistor goes Low.
T r ay S et Detecti n g S witch
S witch Act u ato r
OFF
ON
Leve r
T r ay 2
s 6115-037