Sensors - Epson Stylus Pro 9000 Service Manual

EPSON Stylus Pro 9000

SENSORS

The following sensors aid in the paper feeding process.
P-FRONT sensor
This sensor is attached to the back side of the Lower Paper Guide and is
an optical (photo-reflective) sensor. This sensor detects the front edge of
the paper after paper has been loaded but before it is set and ready to
print.
P-REAR sensor
This sensor is attached to the back side of the Upper Paper Guide and is
an optical (photo-reflective) sensor. This sensor detects the rear edge of
the paper as an end of page and detects the front edge when the paper is
first inserted in the paper path.
P-THICK sensor
This sensor physically gauges whether the paper in falls into the normal/
thin category or the thick category. The Secondary Roller unit closest to
the HP has a thin metal flag on top. When the Paper Release Lever is in
the Lock position and thin paper is loaded, this flag enters the space
between the sensor's light emitter and receiver. However, when thick
paper is loaded the flag is forced forward out of the sensor area, signalling
that thick paper is loaded.
Sensor signal = "ON" at 0.7V or less:
Sensor signal = "OFF" at 2.4V or more: Thick paper
Paper Release Lever Position sensor
The Paper Release Lever is located on the right side of the printer, and this
sensor is attached at the bottom of the lever, inside the right-side frame.
This sensor's signal goes "ON" when the lever is in the lock position,
meaning it is OK to print like a mad man.
Operating Principles
Normal/Thin paper
Description of Components
P-REAR
Sensor
P THICK
Sensor
Paper Release
Lever
P-FRONT Sensor
Figure 2-10. Paper Feed Sensors
Revision B
Paper Release Lever
Position Sensor
41