Are you in the habit of removing the empty ink cartridge from the printer and taking it to the store with you when you buy a new one? This may be a bad habit to get into. Here's why.

You should only remove an empty ink cartridge when you can replace it immediately. When you remove the ink cartridge, it allows air to enter the print head and cleaning assembly. This can cause the ink to dry out in areas that really need to remain moist. This can cause irregular printing or color problems when the new cartridge is installed.

Obviously a short amount of time won't be a problem, but leaving that cartridge out of the printer for long periods of time may be problematic.