How do I know when an ink cartridge needs to be replaced?

• When the printer's red Error light flashes, an ink cartridge is getting low on ink. This is a good time to make sure you have a new cartridge handy. When the Error light stays on, a cartridge is empty and you need to replace it. The Error light also stays on if there is a paper jam so make sure the paper feeds properly before changing the ink cartridge. You can check your ink supply by double-clicking on the Printer icon on your taskbar or the Ink Monitor icon on the taskbar (Windows) or from the Print menu (Macintosh). You will see a window showing the amount of ink remaining.