Run out of Ink

[PM2019]

Although I subscribe to HP Instant Ink, I appear to have run out of ink and no cartridge has been sent.  My printer reports the black as low but the colour is showing half full.  When I try to print, the black print is missing areas and is unreadable, and there are lines through any colour printing.  I rarely print and  the last time HP sent me ink seems to have been two years ago and I therefore wonder if the ink is actually drying out without me using it.   But I don't remember being told to regularly print to keep the cartridges from drying out.  

[8lives]

You are correct, the ink has dried in the printhead of the cartridges.

You need to use a inkjet at least once a week.