Black stains at the edges of the printout - Brother MFC 2710 DW

[Brotheralex]

Hello everybody,


I already spent some hours in the internet searching for a solution for my problem, but I was not successful.
My last hope is this place.

I have a Brother MFC 2710 DW and since a few weeks evey piece of paper that comes out of the printer has black stains at the edges.

Attached you can find an image of a printout. The area in the red box should be white but as you can see there are black spots everywhere.

Things I already did:

- replace the cartridge
- replace the drum unit
- clean every inch of the printer inside.

Have you ever seen any misprint like mine before?
Do you have any ideas what I can do to solve the issue?

Thanks a lot for any tips in advance!


Best regards,
Alex