Bob-
I think the reason the paper is curling is due to the fact the image is 
bonded to the paper with heat in a laser printer. Paper coming out of any 
thermal printer tends to curl. If you are old enough to remember the first 
copier on the market back in the 60's the "Thermofax" made by 3M. It was 
horrendous for curling the paper. I think some other brands that don't curl 
as much have another roller after the heat setter roller that reverse bends 
the paper so they come out flat. We used to take the Themofax pages and pull 
them down across the edge of a table or sharp edge with the back towards the 
edge to take the curl out. They would usually curl again in a day or so, 
particularly if the humidity was high. The side of the paper with the print 
on it cannot expand as much as the blank side.
Suggest you Google "How does a laser printer work". You will find numerous 
explanations of what happens inside the machine.
HTH
John Dinges 

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