this seems like it's stating the obvious, but bare with us for a moment.
black pens are more complicated than they seem. I have known some student midwives purchase some beautiful pens that have things engraved onto them, or that just generally write incredibly well.
but before you make an expensive purchase, you have to know that people steal black pens.
there! I said it!
all joking aside, people genuinely do steal black pens - not that they all mean to, but it's very easy to simply borrow a pen from someone and then forget to return it, especially when you're working long shifts and are balancing a heavy workload.
in terms of affordable black pens, I much prefer the zebra z-grip ballpoint pens compared to your classic bic ballpoints. I generally feel that the colour of the zebra pens tend to be much darker and generally look nicer when writing in women's notes.