Faded pages after getting new toners for Laserjet M15w

I have an HP M15w with 1000 text prints put through it. I noticed that the prints contrast was fading and I changed toner for the second time since I bought it. But the contrast of the prints didn't recover after changing the toner. I have found very little non-HP information on the internet on how to diagnose the problem. The information provided by HP was mainly focused on discouraging purchases of toners from other manufacturers than HP. I have tried to shake the toner and knock it on a table. In the beginning, shaking it helped a bit perhaps. I have purchased a second toner, and the proble

Question by Mikkel Rev on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.