I only read this post after replying to your PM. I don't own the Olivetti you mention, so I don't know if it has a traditional ribbon system as well. The carbon ribbon systems that I've come across are typically one-way only, and because of that smaller in size. Loading it with regular ribbon - assuming it fits - would mean swapping the ribbon after each pass, and this is also assuming the supply and take-up spools are the same.