Page: 32
Service Guide OL400
Chapter 2 Principles of Operation
2.5.02 Sensor Functions
At Power-On
The inlet and outlet sensors are checked for their on and off states at power on.
Inlet sensor ON: Inlet jam error (Paper supply jam)
Outlet sensor ON: Outlet jam error (Paper eject jam)
The thermistor sensor circuit detects if the temperature of the fusing unit reaches the normal
temperature within the specified time. When it does not reach the normal temperature within the
specified time, the thermistor sensor turns OFF the heater and generates an alarm.
During Hopping
Whenever the inlet sensor fails to detect paper within a predetermined period of time after a feed
command has been issued to the paper supply system (tray), the failure is counted. A hopping
operation is then attempted up to three times, and if the paper still fails to feed properly, an inlet
jam error is established.
During Feeding
If the leading part of the paper does not reach the outlet sensor within a predetermined period of
time after the start of feeding by the resist motor, a feed jam error is established.
Detection of Form Length Errors by the Inlet Sensor
Any form length other than 11 or 14 inches will generate a form length error, causing an alarm to
be set. To detect the form length, the processor counts the time from when the inlet sensor turns
on until it turns off (after the start of the resist motor in the forward direction). Form length
detection is not enabled for manually inserted paper or envelopes.
Detection of Outlet Jams by the Outlet Sensor
Since paper is fed through the printer at a fixed speed, the outlet sensor must remain on for a
predetermined length of time. If the sensor remains on in excess of this time, the controller
assumes that an exit jam has occurred and an alarm is generated.
Copyright 1997, Okidata, Division of OKI America, Inc. All rights reserved. See the OKIDATA Business
Partner Exchange (BPX) for any updates to this material. (http://bpx.okidata.com)
