I have a Sharp EL-1801P that is low on ink. Can I add ink to the roller or do I need to buy a new roller?

Ink roller: Type EA-772R
WARNING: APPLYING INK TO WORN INK ROLLER OR USE OF
UNAPPROVED INK ROLLER MAY CAUSE SERIOUS DAMAGE TO PRINTER.
1) Set the power switch to OFF.
2) Remove the printer cover. (Fig. 1)
3) Hold the top of the ink roller and remove the roller by pulling
it toward you and then upward. (Fig. 2)
4) Install the new ink roller in the correct position. Make sure
that the roller is securely in place. (Fig. 3)
5) Put back the printer cover.