I'm also having issues with printing through airprint.
I have Synology DS211j, Canon MP610 installed as Network printer (network printing works OK) - enabled Airprint, selected the Canon/MP510 printer, activated Bonjour.
The iPhone and iPad do recognize the 'Usbprinter1' as Canon MP610, then sends stuff to the printer, but nothing happens
Big bummer !
Any other folks having (positive) experience with Airprinting with the Canon MP610 ?