I've only tried to run artist's acetate through a 
copy machine once; it was too thin, and ended up 
with all kinds of roller-marks. I might try again 
with a thicker size... but if you're going to use 
a copier for your lines, you should use 
acetate/overheads that have been designated for 
copiers or printers. Someone at my husband's work 
tried running non-copier overheads through the 
copy machine, and ended up ruining their machine. 
@_@

There are other things to worry about when using 
a copier. The toner might not be good, and might 
be easily susceptible to flaking. You get a 
problem with stray toner all over the place, and 
if the person you go to hasn't cleaned their 
machine in a while, the acetate comes out looking 
junky. So it's fine when it works... but there 
are so many variables you don't have control over 
that can really mess things up. ^_^

Good luck!