Copy machines store everything you copy.

It seems to me that an astute manufacturer could garner good publicity and extra sales (especially to sectors like medical and law enforcement) by incorporating one or both of the following features into their machines:

• 'ghost' (a toggled option, like stapling - automatically erases the document from memory after the copy/print/scan is done by writing zeros to every block it had occupied);
• 'zero' (admin option which zeros the entire document-storage portion of the hard drive)

Jam it back in, in the dark.