If you have an AirPrint-enabled printer, you can print photos and documents from your Mac without having to download and install printer drivers.
You can use AirPrint to print wirelessly to:
An AirPrint-enabled printer on your Wi-Fi network
A network printer or printer shared by another Mac on your Wi-Fi network
A printer connected to the USB port of an AirPort base station
Print to an AirPrint printer. When you print from an app, click the Printer pop-up menu in the Print dialog, then choose a printer in the Nearby Printers list.
Can’t find the printer you’re looking for? Make sure it’s connected to the same Wi-Fi network as your iMac. If it’s connected and you still don’t see it, try adding it: open About AirPrint.