To expand on the above, the method of using an ImageWriter with OS X depends on leveraging CUPS, which also happens to be the standard printer support infrastructure for Linux (and most other free UNIXes these days). Therefore it might actually be more straightforward to run the Imagewriter on a Linux machine (you could use a Raspberry Pi or something via a USB-> serial adapter) and share it via Netatalk.
Of course, with *either* the OS X or Linux solution you'll need a localtalk/ethertalk bridge if you intend to share the printer with localtalk hosts, because OS X doesn't support Localtalk even on machines that have the hardware.