QTR-Quadtone RIP

I'm wondering if when applying different color inks, even different
black inks, how the printer applies these. Are the colors "mixed" so
that a particular dot of ink can be a mixture of more than one ink
color? And to do this, what would the QTR curve settings (density,
limit) be say if I wanted to lay down only red dots made up of magenta
and yellow inks?   

Or does it lay down the individual colors as separate dots that the
eye sees as a new color--for example, a red color is acutally made up
of separate magenta and yellow dots of ink. 

Best, David.