Canon has announced that it has added AirPrint support to three PIXMA printers. According to the announcement, the PIXMA MG8220, MG6220 and MG5320 Wireless Photo All-In-One inkjet photo printers will now support AirPrint wireless printing from the iPad, iPhone and iPod touch. In addition, the company also announced that the majority of PIXMA inkjet printers launched from this point forward will include support for the feature. Introduced in iOS 4.2…