I acquired this really neat Citizen till roll printer a while back, but only got to re-inking the ribbon last year and then it started giving problems. I was about to throw it out and decided to try it one last time with a decent power supply made up using an old laptop adaptor and one of the awesome little switch mode voltage converters I got on eBay recently. With 2 amps and a nice stable 7 volts the printer is now working a treat. On the self-test you can see the gobbledygook when the printer was attached to the old linear power supply and underneath the correct print out using my DIY switch mode supply.
The printer is serial with a standard RS232 interface that should connect to a USB-to-serial adaptor. There are a few interesting 'Internet Of Things' (IOF) projects using small printers and a Raspberry Pi or an Arduino could send serial data out to be printed locally. A few experiments are in the pipeline I think!