Your roller should always feed your paper Square to the rollers with very little effort.
When your roller has any problems feeding sqaurely on a consistent basis it's time to disassemble and clean.
If your rolllers look like this
and your roller apron looks like this
It is way past cleaning time.
I just disassembled the rollers and aprons then threw them into some used bong cleaner for a few minutes
Everything reassembled, Straws placed in the natural fold of the apron, This keeps the shape of the apron consistent while it's while it waits until it's next use
Doing this will break in the apron keeping it in shape while the straw is out for long periods without trying to go back into it's original shape which if it does will usually
dump your weed out.