Q:

How can I use software and printer technology to get the smallest possible resolution for my printouts?

I am making something that is supposed to function like a miniature projection slide. So I want to print some black figures (mostly lines and circular dots) with very small dimensions (0.3 mm and smaller) on transparent A4 sheets. I will then inspect the figures using a microscope. In the past, for similar things other people have used a 5080dpi laser printer.
Now my question is: How can I use software and printer technology to get the smallest possible resolution for my printouts?
The printshop I go to says their best printer is the Ricoh pro c7100sx, which I checked has a printing resolution of Max. 1200 x 4800 dpi VCSEL.
I am designing my figures in inkscape. However any other software and printer 
suggestions are  welcome too.
More specific questions:
When I save my design to pdf, inkscape lets me rasterize the document. Should I do that? And if so, how many dpi should I use for the rasterization? Or is it better to leave the rasterization up to the printer software?

A:

You should always stay in vector format. It's infinitely scalable.
The resolution of the output device is key. The best result will probably be delivered by a laser film printer, around 5000-6000dpi (as you already mentioned) or even higher, which is usually used to create a positive film for producing offset printing plates (incl. the fine screen raster dots). It's 100% sharp and black, through a photographic process, no toner.
 
You have to look for a PrePress Service to find someone with one of those printers. I think the industry moved to direct-to-plate, so these film printers are not as common as they used to be 15 years ago.
 
The results with ink or toner printers will probably not be so satisfying. However, they are fast and cheap and easy to try out.

