Estimted Cartridges issue (HP Ink Tank Wireless 415)

[Achro]

[DETAILS]
I tried to print a document (all black), and the entire page is faded. I proceeded to check customer support pages and stopped at Step 6, printing a Quality Diagnostic page. I printed the same document four times (the last two being the results after using the Clean Cartridges feature) and they all have the same outcome; all colors are present except for black. 

Before that, I also checked the ink cartridges several times, and the ink levels are more or less just a cm away from the Maximum fill line.

[MAIN PROBLEM/QUESTION]
When I checked the Estimated Cartridges tab, it shows that all tanks are completely empty; yet neither has a caution symbol. Reminder; every other color prints except for black, and when I checked the cartridges, they're way too far from the minimum fill line. Does this mean the ink has dried up, or does this mean something else? Thank you in advance!

[Valsimot · Accepted solution]

On your printer model, only visual inspection of ink tanks is a way to know ink level. The estimated ink lever on your computer will always be blank because the printer doesn't monitor the ink level. 

Regarding print quality, if your printer hasn't been used for a while liquids ink gets dry inside printhead, running a few cleaning cycles a few times might get your black to start printing again.

[Achro]

I just followed your advice, and after more or less twenty cleaning cycles, the black ink returned and the colored ones look better. Thanks for the comment!

[CrazyWolf111]

Same problem  on this same model. Left printer for 2 months and now will not print in black at all, colors do print.

I've tried cleaning over 20 times - but still no black ink (tank is full).  What should I try next?