Reset - HP Deskjet 3920 Color Inkjet Printer

The Print Carriage is Stuck and Won't Move
HP Deskjet 3535, 3744, and 3920 Color Inkjet Printer

Issue

If the printer fails to print, the Power light is blinking, a Mechanism Error is displayed on the computer, or the print cartridge carriage won't move back and forth across the printer, the carriage may be stalled.

Solution
Follow the steps below.

Step one: Check for paper jams

1. Unplug the printer power cord.
2. Open the rear access door and remove any paper from the paper path.
3. Reattach the rear access door and reconnect the power cord. The unit should re-start and move the print carriage to the normal position.
4. Try printing again. If the carriage still won't move, or makes a grinding noise, continue on to the next step.

Step two: Reset the printer

1. Unplug the power cord and remove the paper from the paper tray.
2. Move the carriage all the way to the right, close the lid and reconnect the power cord.
3. The printer will make some noise as it starts back up. Wait until it stops making noise.
4. Open the printer lid. The carriage should return to its normal position.
5. Try printing again.

Source : http://welcome.hp.com/country/id/en/support.html