Ever wanted to print something from your phone, but didn't have a printer around? No? Well, somebody out there probably has at some point, and this is just the invention for whomever that person might be.

It's a smart phone case with a printer built in, that prints onto normal paper. It has an inkjet in the middle of the face, and motorized ball bearings on each corner so it can crawl around the page.

When you set the phone on the paper, it uses the phone's camera (in conjunction with a macro lens built into the case) to locate a corner of the page and orient itself. If the user hasn't specified the paper size, it then travels along the edge of the page until it locates the opposite corner. Having determined the paper format, it begins at the top left corner of the page and prints the document row by row as it moves back and forth down the page.

The paper detection settings can be disabled in order to simply print freeform, of course. And since the motorized bearings are also capable of sensing motion, you can even print in the vertical orientation (such as on a wall or on the side of a box) by manually moving the phone across the surface. In this configuration, the camera can be used to detect previously printed lines to aid the software in orienting the output for multi-line printing.
-- ytk, Sep 25 2013

random, halfbakery