There are two methods to get black and white printing on a mac.
The first is the recommended method, however it is possible to use the second to override colour settings when you reach the printer and force black & white.
Open up the Print menu, Click "Copies and pages" then select "Color Matching"
Ensure ColorSync is selected and Change it from Automatic to Generic gray profile by selecting other profile. Then select Ok.
Save the current settings as a preset for future use by clicking default settings and selecting Save Current Settings as Preset.
Type in a meaningful name eg "Black and White", click OK.
In future you can select this preset from the list to print in Black and White.
The second method is to simply use the default preset then when at the printer, press the button that says "Force Monochrome".
This will remain selected for all printing from your account until you press it again to "untick" it at the printer