What should I do when a 'Cartridge is low' or 'Cartridge is very low' message appears on the control panel?

When these messages appear, consider having a replacement cartridge available to install when print quality is no longer acceptable. You can also change the 'Very Low' settings to control how the printer behaves when toner is critically low. For printers with fax capability, additional options are available to manage this condition. (Page 115)