Brother HL-2600CN Series - Manual (Page 153)

CHAPTER 5 MAINTENANCE
5-41
14. Remove all the Toner Cartridges from the printer.
15. Use the fingers of both hands to hold the two knobs on the Dustproof
Glass, and then remove it from the Laser Unit by lifting it up.
Fig. 5-48
16. Clean the surface of the Dustproof Glass with a dry cotton swab.
Fig. 5-49
17. Re-install the Dustproof Glass by aligning the ▲ marks on the Laser Unit
and the Dustproof Glass; This will ensure that it is correctly in place and
cannot move.
Fig. 5-50