Quiet, more colourful piece of office equipment (8)
I believe the answer is:
shredder
'piece of office equipment' is the definition.
(I've seen this before)
'quiet more colourful' is the wordplay.
'quiet' becomes 'sh'.
'more colourful' becomes 'redder' ('red' can be similar in meaning to 'colourful').
'sh'+'redder'='SHREDDER'
(Other definitions for shredder that I've seen before include "security equipment" , "Paper-cutter" , "Office security device" , "piece of office equipment" , "one destroys paper" .)