Here's a few things to try :

1. Blow it out with canned air. make sure there are no bits of paper or dust in the paper feed area and in the front access area that could be causing the jam.

2. Verify that the cartridge carriage moves to the service area when the front door is opened (as if to change tanks)

3. Verify that the timing belt, drive belt, gearing and rollers all look normal.

4. Take the network out of play when doing the initial troubleshooting

5. With the computer off, unplug the printer's power cord and USB cord for about 3-5 min

6. Completely uninstall the printer's driver and software. Then reinstall the printer's drivers only.

Retry after each step.