I won a Sega SP-400 Plotter Printer in a YouTube auction last week. I was very excited. I've wanted one of these since I was a kid and I missed out on the last one auctioned on TradeMe about three years back.
It arrived yesterday, and I was able to get the self-test running last night and this morning I typed in a demo program that drew a nice coloured pie chart.
They are based on a standard ALPS mini-plotter mechanism that was used in a lot of home plotters in the early 80s like the Commodore 1520 and the Atari 1020.
This thing is neat, and funnily enough almost seems contemporary if you've watched a 3D printer in action - it almost has that sort of feel to it. It has 4 pens and it works by moving the paper up and down while the pens move left and right to draw on the roll of paper.
If I get some spare time, I'll add some plotter demos to the Sega SC-3000 Multicart.
Anyway - enjoy

YouTube Initial unboxing / printer self test demo
https://www.youtube.com/watch?v=sck-A3dy6g0
YouTube Pie Chart demo (typed in from the SP-400 user manual)
https://youtu.be/hB3gYiBw214
Cheers