First of all, use the proper ink to refill LC-51 cartridges, only use high quality ink. If you don't, say good bye to your printer. There are to many people on here using HP ink to fill Brother cartridges, or left over Canon ink to fill Brother cartridges, this is wrong. If you are going to refill, then refill properly, and don't cut corners like that, unless you plan on throwing out your printer and purchasing another.