Copy I place wrongly under back of printer (7)
I believe the answer is:
replica
'copy' is the definition.
(replica is a kind of copy)
'i place wrongly under back of printer' is the wordplay.
'wrongly' is an anagram indicator.
'under' says to put letters next to each other.
'back of' suggests the final letters.
The last letter of 'printer' is 'r'.
'i'+'place'='iplace'
'iplace' is an anagram of 'eplica'.
'eplica' put after 'r' is 'REPLICA'.
(Other definitions for replica that I've seen before include "Reproduction, exact copy" , "Parcel I arranged as exact copy" , "Parcel I made into an exact copy" , "knock-off" , "Exact copy or model" .)