If I were working on a paper pieced block, I would use a standard copier (assuming the paper size is large enough - I have 11x17 paper on hand if I need it for large projects), and be certain to make more copies than I think I need, so as not to have to return to enlarging at a later time. I wouldn't want to risk the size coming out a hair different on the second trip to the copier.
Cheers, K