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For "toner movement"?  Please explain.  Do these steel spheres come  
out of printers/plotters?

If you gently stir a mixture of metallic particles and pigment laden plastic powder, the plastic powder and the metal particles will aquire electrical charge due to "tribocharging".  This is much the same as rubbing a balloon on a cat's fur.  In a laser printer or copier, the toner mixture is lifted via a rotating segmented magnet which brushes very gently againt the imaging drum of the machine.  This arraingement is called a magnetic brush. the pigmented rplastic adheres to the charged part of the imaging drum and is ten transfered to paper.  Finally the paper passes through the heated rollers of the fuser and is permanantlhy bound to the paper more or less as a hot melt glue. 

If you want more details consult the US Patent and Trademark Office, it's free and relatively easy to do these days. 
First, search to find the relevant patent number(s)

http://www.uspto.gov/patft/index.html

To retrieve the document in readable pdf format goto:
http://www.pat2pdf.org
type or past in the patent number and pat2pdf will agglomerate the patent for you to download.

Hve fun!!

I'm sure glad the xerox people got away from using all those rabbit skins to charge their toner!

Reagan Cole,
Durham, NC

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