What is Bluetooth and how does it work?
Bluetooth wireless technology allows Bluetooth-enabled printers, computers, PDAs, mobile phones and other compatible devices to communicate over radio waves in the 2.4 GHz spectrums over short distances, up to 32 feet (10 meters). Unlike infrared, Bluetooth wireless technology does not require a direct line of sight between the sending and receiving devices.
Bluetooth technology uses tiny, short-range wireless radio modules that are embedded in devices, either directly or through an adapter, such as a PC card. When a print job is initiated from a Bluetooth-enabled PDA, computer or mobile phone, the device will list devices with Bluetooth wireless technology within range to which it can connect.
Bluetooth devices supported with the HP Deskjet 450 printer
The HP Deskjet 450 printer supports direct printing from select Bluetooth-enabled PDAs, mobile phones and computers. The following table lists compatible Bluetooth-enabled devices.
 

From HP: The HP Deskjet 450 printer uses the HP Bluetooth printer card (C8249A) . To purchase the HP Bluetooth printer card, navigate to the HP Web site and enter the part number C8249A in the Search box and then press the Enter key on the keyboard. On the Search results page under the HP Bluetooth Printer Card, click Product overview to see the HP Bluetooth Printer Card features and purchasing information.