I believe the copyright is only valid 20 years, second since you aren't selling the copies there is no violation. If that was the case teachers would have been fined a long time ago.
Will work for shrimpz.......
Copyrights can be renewed.
And teachers can get fined for breaking copyrights if they don't have permission to make those copies. Does not have to be for resale.
Many academic institutions actually buy permission to make copies (such as universities to put together excerpt/article packets for classes, etc)