UV ink refers to "UV cured" ink, a type of ink that becomes virtually indestructible when exposed to high intensity UV light. Without that light, it never really dries. It is also chemically incompatible with whatever ink residue is in the print heads and lines of your printer and requires a "virgin" printer. And a printer with lines, heads, pumps, etc. that can withstand the chemicals in the ink.
If you want better UV blocking, try reloading carts with MIS carbon pigment black inks of various dilutions. Carbon pigment black has the best UV blocking of any type of ink, and it is totally consistent from batch to batch, because it's simply light stopping carbon particles.
All digital negative making methods based on color inks are fatally flawed: they put you at the mercy of the ink manufacturer, who only cares about the UV performance of inks as it relates to the fade resistance of the color inks. The UV performance isn't well controlled and changes from batch to batch of ink.