AirPort Utility 6.x: Use a USB printer on your Wi-Fi network
If you connect a compatible USB printer to an AirPort Extreme Base Station, AirPort Express, or Time Capsule, all the computers on the network, both wired and wireless, can print to the printer.
Before you connect the printer to the device, connect it to a computer and print a test page.
After you have made sure the printer is working properly, connect the printer to the wireless device’s USB port.
On a Windows computer: Install Bonjour for Windows from the AirPort Utility CD, and follow the onscreen instructions to connect to the printer.
Error or status messages may not be available when the printer is connected to a wireless device. For example, you may not get messages such as “Out of Paper” or “Printer Busy.”