Is this sentence OK?
I printed the document to the copier to be stapled and double-sided but it came out as unstapled and one-sided. The copier's functions are not working.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
At my last office, we had a photocopier which could be programmed to do double-sided printing and stapling of the copies which emerged. Admittedly, it wasn't connected to any computers so we couldn't "send" documents to it. We had to insert the original document but if the OP's original piece is changed to "I set the copier to do double-sided copies and staple the copies but they came out stapled and single-sided", then it works with "copier" or "photocopier".
Whether "printer" or "copier" is correct depends entirely on the piece of equipment the OP is talking about.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.