my Brother DCP-135C wont print in Grayscale even after i set grayscale in every setting i could find. I have set greyscale in the settings but anyways every document i print is in color. I have installed the official brother driver from the brother support page because the pre-installed printer driver which came with ubuntu didnt work with the printer and it didnt print at all.
How can i get my printer to print in greyscale so i dont have to waste the color?

Thank you for the help.
Using Ubuntu 20.10 64bit