using printer with tank for stencil

hi everyone

i buy a canon pixma and add stencil ink inside. but cartriges of machine have already some inks inside. i am not sure what should i do now. should i use all other black ink inside of the machine before add stencil ink or is it possible to find another way?

I've only have used thermal printers but I have seen people use the economy tanks from espon for printing stencils but I don't know what other printers are used