It sucks
The service notes are silent on the service life or service interval. I supposr I would take a look at inside every couple of years--or when the suction loss becomes a problem.
I didn't take a photo of it, but the small space inside the printer where the fan blows out was also covered with a substantial amount of
paper dust. This is where all of the heater junction boards live.
Anyway, it's easy to get access to the fan (just remove the rear cover) and pull it out (held in with two 3mm allen head screws). However, it's a total pain in the ass to put it back in. You have to line up the fan, a foam gasket and a couple of spacers... but the space is only a couple of inches in height. Not an easy chore of you have a large hand or arm.
It's not a super technical repair, but it's not a quick and easy fix either. Takes a good 30-40 minutes.
~E