I have a D420 that does single-sided printing perfectly. However, when I try to print duplex (second side), the back side is printed and the paper begins to rewind, but gets slightly crooked and is detected as a jam. I can't figure out what rollers to clean (etc) to get the reverse/print-other-side mechanism to work.
Is there a repair / maintenance procedure for getting duplex printing working again?
In this situation, it looks like there is something wrong with the paper feed. You can try removing all of the toner cartridges and wiping any of the visible rollers with a damp cloth. If that does not resolve the issue, it will usually mean the printer needs service. Outside of the 1 year warranty, you can contact our sales department at 1-800-385-2155 to use our Upgrade Program. The Upgrade program will give you a discount and free shipping on a replacement printer.