CHAPTER 4 TROUBLESHOOTING IMAGE FAULTS/MALFUNCTIONS
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6.1.2 Checking the Photointerrupters
The photointerrupters are checked in service mode; go through the tables attached to the
lists of electrical components to find out the state* of a specific sensor, which may be any of
the following:
a. Paper Sensor
Move the sensor lever by hand to simulate the presence of paper; then, check the Service
Mode screen.
If it is difficult to check the Service Mode screen while moving the sensor lever, put paper
over the point of detection, and then check the Service Mode screen.
b. Open/Closed Sensor
Check the Service Mode screen while opening/closing the cover/unit in question.
c. Position Sensor, Presence/Absence Sensor
Move the unit in question by hand. Try removing and then mounting it. If the I/O level
changes in response to operation, the sensor may be assumed to be normal.
To check a photointerrupter found inside a unit which is detached in con-
junction with a drawer connector, be sure to check the Service Mode while
the unit in question is set.
*The state of a sensor refers to any of the following:
•
For a paper sensor, the presence or the absence of paper.
•
For an open/closed sensor, the state in which the cover/unit is closed.
•
For a home position sensor or a set sensor, the item in question is in home position or set
in place.
