The "Arm Swing Gear" for the HP LaserJet 1010 printer is a part related to the printer's paper handling mechanism. The HP LaserJet 1010 is a laser printer, and this gear is a component used in the paper feed system to assist in moving the paper through the printer.

In particular, the arm swing gear typically helps with the movement of the feed roller assembly or other parts that move the paper from the input tray through the printer during printing. When this gear wears out or gets damaged, it can cause paper jams, incorrect paper feeding, or failure to print properly.

If you're looking to replace this part, you may need to:

1. Disassemble the printer: Carefully open up the printer to access the paper feed mechanism.
2. Locate the Arm Swing Gear: The gear is usually located near the paper feed rollers and may be connected to the printer's drive motor.
3. Replace the Gear: Once you have the correct replacement gear, you can install it in the same position.

If you're unfamiliar with printer repairs, it might be helpful to consult a service manual or reach out to a professional technician.

For purchasing the part, you can check online marketplaces, authorized HP service centers, or printer repair shops that sell replacement parts for the HP LaserJet series.