SECTION 4
MEASUREMENTS & ADJUSTMENTS
46
Media Sensors
Feed Sensor
The feed sensor detects the media as it feeds between the sheet separation area and the print engine.
This is a retro-reflective sensor.
The sensor is located below the deck of the printer (see image below).
The sensor looks up at a reflector, which is attached to the underside of the plate on the center pressure
rollers.
When the paper passes between the sensor and reflector, the light beam is broken and the sensor
responds as being interrupted (paper present).
Feed Sensor Tests
Remove the non-operator side cover to access the Feed Sensor and I/O Board.
There are three ways you can test the Feed Sensor.
1 - Measure sensor output at the I/O Board: between GND and TP4:
0 V open (no paper); 7.5 VDC interrupted (paper present)
2 - Check the LED conditions at the sensor:
Open (no paper) = Both Green & Orange LEDs are illuminated
Interrupted (paper present) = Only the Green LED is illuminated
Tip: We have seen a few cases where the sensor is lazy (due to dust/damage/improper adjustment
or reflector angle) and it will toggle when you give it enough time to do so, but it may not always
toggle at the small gap generated between pieces. To test for this possibility; interrupt/uninterrupt
the sensor quickly, while watching the LED conditions.
3 - You can use the resettable job counter to test sensor function.
As paper interrupts this sensor the job counter will increment by one.
Feed Sensor Adjustment
The potentiometer, located on the bottom of the feed sensor (see red arrow in the image above) is used
to adjust the intensity of this sensor. In general, the intensity will be set to MAX. However if you have
a glossy piece of media that is being seen as open (no paper), when it is over the sensor; you can try to
adjust the sensor intensity lower until the sensor reads correctly.
Cleaning Note: The Feed Sensor should be cleaned using compressed air and a soft bristled brush.
To avoid splattering ink through-out the print engine; do NOT blow air into the capping station or onto
the wiper roller. Tip: If cleaning and adjustment does not cure issue, as a last effort before
replacement, you can try to clean with a damp cloth or cotton swab.
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