How to use only black cartrige with pixma mg5250

[AlbertTime]

Hi i would like to know how to use only black cartrige with pixma 5250 , 

color cartrige get very fast empty even when i only print in black and white 

i dont see any print in grey option i use a mac system 

is there a way to crack the system or to force using black ink cartrige 

with this model 

thank you for answears 

best regards