Beginning with Android 4.4 (Kitkat) manufacturers of computer printers can provide apps to support the Android printing framework. Apps like Gmail oder the Android Media Manager support this framework to enable users to print content like mails or pictures directly from a smartphone.
Typically the printer used is not connected via USB cable directly to the computer but connected to the home network via Wifi or a LAN cable. Many of the common printers already support Wifi.
E-PasswordCard (1.2) provides printing for smartphones with Android as from version 4.4 through it’s “print” menu.