My impression is in case you can uniquely identify the hardcopy and longterm archive that till the end of the medical device lifetime, than basically you have nothing to do with the scanned one.
If you want 1oo% sure, for each scanned paper write a statement saying "can not be used as a valid copy of the original hardcopy" or something similar, excluding its formal usage.
The problem is coming from part11 guidance, saying:
"
if a record is required to be maintained under a predicate rule and you use a computer to generate a paper printout of the electronic records, but you nonetheless rely on the electronic record to perform regulated activities, the
Agency may consider you to be using the electronic record instead of the paper record.
"
http://www.fda.gov/RegulatoryInformation/Guidances/ucm125067.htm
Nevertheless this is a case you shall avoid, otherwise you shall validate the document scan system.
regards
Sz.