Genuine OEM HP PSC 1315 xi Ink and Supplies
The PSC 1315xi's HP 27/28 and HP 56/57 packs each combine black with tri-color ink. If you're keeping a spare of just one ink, the HP 27 black, HP 56 black and HP 57 tri-color twin packs are the same-ink options.
Toner Buzz carries genuine HP 27, 28, 56 and 57 cartridges as singles and in these packs, alongside HP 58 photo ink. Pick a single for the ink you're using up, or one of the mixed combos for black and color together.