If you think your photocopier is producing exact duplicates of your documents, you might want to double-check — some popular Xerox scanners and photocopiers change text and numbers documents scanned and copied under the "normal" quality setting.
There are a lot of times when this could be very bad.
Based on the way the commercial copiers at work operate, I'm guessing this is happening because the copiers are now using scanning technology rather than copy technology the old copiers used (remember they were originally called photo copiers). Most of the new copiers are copy, scan and fax combination machines. The machine scans the document and then depending on which selection you make will print a copy, scanned document file or fax the document.
In working with scanners, even the most recent ones will once in a while change letters. The colors of the original ink or paper or defects in the paper will confuse the scanning software and it will best guess.
The advantage to copies made by scanning the document and the capability to save it as a digital file as well as print it; allows for changes to a document where the old copies were images and could not be changed.
If the new copiers are using this same scanning technology you can expect errors.
So now-a-days a copy is not a pretty picture, it's a bunch of bytes.