Work on papers is burden (7)
I believe the answer is:
oppress
'is burden' is the definition.
(I've seen this before)
'work on papers' is the wordplay.
'work' becomes 'op' (abbreviation for opus).
'on' is a charade indicator (letters next to each other).
'papers' becomes 'press' (the newspaper industry).
'op'+'press'='OPPRESS'
(Other definitions for oppress that I've seen before include "Subjugate or weigh on" , "Distress" , "Lie heavy upon" , "Afflict" , "Abuse" .)