Error 5100 on printer?

This issue could or could not be with the printer itself. Try these steps below.

1. Turn off printer
2. Hold down Resume button and press Power button.
3. Keep holding down Power button and let Resume button go.
4. Press Resume button 2 times then let BOTH buttons go.
5. Green lights will flash and then stop blinking.
6. When green lights are solid, press the Resume button 4 times.
7. Press the Power button and the printer should turn off, if not,
press the Power button once more.
8. Run a test page, your printer should respond as normal.

If the steps above does not work for you, then you need to check printer for obstructions by checking the inside of your printer through the gears that you can see under the lid. There should be something obstructing the gears such as dirt. Also,
1. Clean the strip film.
2. Clean the strip film sensor (back of head carriage)(use contact cleaner).
3. Fix purge unit.