Question

why does ink does not flow through from pen even it has hole

Answer 1

Ink doesn't flow from pen because of "Capillary Action'.Once after the ink being inserted in the tube *adhesive force" between the ink and the wall of tube is enough to hold the ink even if it is vertical. Further:- Pen is designed in such a manner that ink follows out of the nib only if it comes in contact with surface like paper. Note:- Pen or Ball of pen generally doesn't work over the surface like plastic as negligent amount of adhesive force between plastic surface and ink. Hope it's understandable why ink doesn't flow out of pen even it has hole.