Oki ES3640MFP Service & Troubleshooting Manual page 74

4.2 Jam Troubleshooting
370: Paper Jam
Condition
Paper jam 370 occurs when the paper is inverted for double-sided printing.
1. The DUP-IN1 sensor does not change to OFF-state within the predefined time after it changed to ON-state.
2. The DUP-IN2 sensor does not change to ON-state within the predefined time after the DUPIN1 sensor changed to ON-state.
3. The DUP-R sensor does not change to ON-state after the paper was inverted in the duplex unit.
The printer stops printing immediately when the jam occurs.
Cause
1. Transport rollers cannot transport paper because they have become dirty with paper dust, toner, etc.
2. A piece of paper, foreign substance, etc., has got stuck in the DUP-IN1, 2 or DUP-R sensor lever.
3. DUP-IN1, 2 or DUP-R sensor motion failure
How to remove the jammed paper
Open the duplex cover - Remove all the sheets that have jammed - Close the duplex cover.
If you have been performing continuous printing, some paper may still remain in
other areas. After opening and closing the cover, if other error code is displayed,
Check Points
Open the duplex unit cover and check the following areas and clean them.
follow the jam clearance method of that code.