If you mean scan as in digitize a paper copy for the purposes of making a copy, there is no sin. Every copier requires the document be scanned before it can be copied. If you mean that when you take the document, you sometimes out of curiosity read over it just to see who those people are, that would probably be a sin. Some jobs definitely require that – I’m thinking here, for example, of mortgage officers that use customer information to run credit checks – but if that isn’t part of the job, you don’t have any business looking at their private information. It can be hard to the right thing in this situation because as part of making a copy or faxing it, you might glance and see a word that grabs your attention. Then you want to see what else it says. Unless you are using the information for malicious purposes, it is probably only a venial sin. But again, if it’s part of your job to look at customer information, you are just doing your job and have no sin.