With some HP DeskJet printers, you need to fool the printer into thinking you have replaced the old ink cartridge with a new ink cartridge instead of a refilled ink cartridge that you filled yourself. If the printer keeps telling you to replace the ink cartridge or the ink level still reads empty, you can reset the printer so that it will recognise the refilled ink cartridge as new and read the ink level as full, or close to it.
Remove the ink cartridge from the printer carriage. Turn the cartridge over so that you are looking at the copper contacts. The contacts should be the closest to you. If the contacts are at the top of the ink cartridge, turn it around so the contacts are closest to you.
Place a small piece of clear tape over the seventh copper contact in the second row of contacts from the left side. Place the cartridge back in the printer. Tell the printer to run an alignment. When the alignment is done, remove the cartridge.
Keep that piece of tape on the contact. On the right side of the cartridge, in the second row from the right, place a small piece of tape over the sixth copper contact. Place the ink cartridge in the printer. Run an alignment page again.
Remove the ink cartridge when the alignment is done. Remove the tape, making sure to remove the sticky residue when you remove the tape. Place the cartridge in the printer. The printer is ready.