There’s some useful information on the Brother website:
Cleaning Brother TN155 Machines
Brother recommend this cleaning operation once a month to keep the best quality.
Other models that use the same consumables are: DCP-9040CN, HL-4040CN, HL-4050CDN, MFC-9450CDN, MFC-9840CDW, DCP9040CN, HL4040CN, HL4050CDN, MFC9450CDN, MFC9840CDW.