First off, you must have an android app device that supports GooglePrint to print invoices. If you do, awesome! Follow the instructions below to print out your invoices:
Note : If you have a printer which could support Bluetooth, then you can print the invoice(s) through the Bluetooth option from your Android app. In this case, you have to download the invoice as a PDF first. Then you can send the downloaded PDF to the Bluetooth configured printer.
For more information on GooglePrint, please visit the http://www.google.co.in/cloudprint/learn/
Zoho Invoice FAQ