While there are plenty of affordable AirPrint-compatible printers out there, you may have already invested in a model that doesn't support Apple's wireless printing protocol. Luckily, adding AirPrint to a non-AirPrint printer is quick, easy, and affordable thanks to a clever Mac app called handyPrint.
Formerly marketed as AirPrint Activator, the rebranded handyPrint works by turning a printer connected to your Mac into an AirPrint printer that's shared over your network. Once configured, you'll be able to print wirelessly using an iPhone, iPad, iPod touch - or another Mac.
What you need
Because this solution requires your printer to be permanently connected to a computer, it works especially well for users with a desktop Mac or a MacBook running in 'clamshell' mode. In this article, we're configuring handyPrint with a Samsung ML-1860 Series laser printer, but you can use any printer which doesn't already support AirPrint. read the rest here