Can't make a Pixma TR8620a printer use black ink only

[Knowalot]

I have a TR8620a Canon Pixma. I'm not asking here. I'm going to give information. Called about selecting black ink and the printer always using all the color instead. Called today. Said to select color. When it sees the document is black, it will select the black ink. Forget that there is no color on what you are printing. Just select color and it will choose the small black ink cartridge. The large black ink is for photos/

[GatorRay]

If the desired print is derived from a website or screenshot with color, selecting color will print whatever is visible in color as color.  Only documents being copied or scanned that are B&W will print in B&W by selecting color.  Not at all intuitive - perhaps for a reason with an economic basis?  If I am not correct then this instruction by Knowalot is not accurate.