HOW TO PRINT IN BLACK ONLY WHEN MULTI COLOUR CARTRIDGES ARE EMPTY AND BLACK IS STILL THERE?

MY PRINTER MODEL IS EPSON WF-7011, MY MULTI COLOR CARTRIDGES ARE EMPTY WHILE I STILL HAVE BLACK LEFT.
WHEN I AM TRYING TO PRINT IN BLACK OR SAY GREY SCALE. ITS NOT LETTING ME PRINT . IT SAYS REFILL CARTRIDGES.
PLEASE HELP ME WITH THE WAY TO PRINT ONLY IN BLACK .