Printer plug in device

I am developing am adapter that sits in between a printer and computer, this adapter woud then intercept print stream data from the computer and attach additional information to the print stream onto the footer of the printed document. This device would need to have both ethernet and USB connectivity. Is this project feasible with Arduino or are there any other existing devices that would allow me to execute this?

Unless it is a plain ascii printer the Arduino is too light.

Buy an Raspberry Pi, install UBUNTU on it and configure it as a print server. Google for CUPS. It includes tooling to adapt printer streams.

Be aware that not all stream can be easily patched. You need a thorough knowledge of the stream (ESC-P, PCL, PostScript, PDF etc)

For a specific printer, it seems feasible (perhaps not using Arduino) as long as you are intimately familiar with the protocol used by the printer.

As a product supporting printers in general, I think you would be taking on a vast job to try to handle all supporter print protocols.

I am mainly trying to use the adapter for Epson receipt printers which from my understanding uses ESC/P. Thank you for the suggestions, Raspberry Pi definitely seems like a better solution than arduino.

How is the printer connected? Serial ?
Do you have a type number of the printer?

The printer's connectivity is either through USB, Serial, or ethernet cable. Mainly using the Epson TM series line of printers. Additionally stumbled upon this

"http://nicholas.piasecki.name/blog/wp-content/uploads/2009/12/ESC-POS-Programming-Guide.pdf"

which might prove to be exceptionally helpful.