Photocopier chemical (5)
I believe the answer is:
toner
'photocopier chemical' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for toner that I've seen before include "Astringent liquid (to improve skin)" , "Powdered pigment used in laser printers" , "Copier powder" , "Material for printer" , "Black or coloured powder used in a printer" .)