Some warmth is normal. The printer maintains a low-power network connection in standby.
Power specifications: 7 watts during operation, 0.8 watts in standby. The 0.8W standby draw is minimal but generates some heat.
If it's excessively hot: Ensure the vents on the back and sides are not blocked. Provide several inches of clearance. A failed component can cause overheating.
To reduce power use: Turn the printer off completely with the power button when not in use for extended periods. The trade-off is you lose instant-on and remote connectivity.
Heads up: This model has higher power consumption than basic, non-wifi printers. The Wi-Fi radio and standby functions require constant power. The warmth is typical for an always-connected device.