Users are comfortable with scrolling. Pagination for articles is often used in editorial sites for ad view opportunities. It does not reward the user to experience a broken narrative in a story for the sake of ad views.
Since you are not making money from advertising (that I can tell), it's a poor user experience even for long articles to have to jump to another page.
Searching thru an article: a poor experience w/ pagination.
Say you have an interesting article with a new concept or word. If I want to see all the instances of this word (and its surrounding content) I can use CMD + F to pull up a quick string search. How could I have continuity with pagination?
As for upvote / downvote buttons, one possibility is to put it to the right side of the header, and have a sticky header. Here's a quick cruddy sketch. I don't have any research as to if they would be better off on top, but a sticky header with infinite scroll would keep the buttons consistently visible.
You should also consider using an up / down bracket icon so users don't have to read the label to discern.
A note on line length and readability
The text you have right now is a bit small, with long line lengths.
You'll notice that most editorial sites use a minimum of 16 pixels for body text, often a bit bigger. Here's an older, but still relevant article:
16 Pixels Font Size: For Body Copy. Anything Less Is A Costly Mistake