Full cartridge but ink not printing.

Did you remove the little piece piece of tape on the bottom of cartridge.

I was having the same problem today. Ran carriage under water and dried. Still didn't work. Looked under tools menu on the printer screen and noticed "clean cartridges." Chose that option. I guess it did the job, because it ran a test print and when we tried to print again it worked just fine.

I just talked to HP support, they said to replace printer because print head is defective. My printer was printing blank pages I replaced all ink cartridge black, cyan, magenta and yellow, it still printed blank pages. My advice, find a better brand. HP sucks.

"This is exactly the issue I was seeing. I washed the head, replaced the inks, changed the printer head... All to no avail. Very frustrating.

At this point, sadly, the most effective solution I can see is simply replace the unit. I've already spent far too much on what is now a defective machine.

Seems such a waste though."

I'm using windows 10, 64 bit and my Officejet 4620 printer wouldn't print black despite having a new HP cartridge. I removed the printer, uninstalled the software and set up the printer again from scratch. It now works.

Get a small but sturdy paint brush (the kind children use for water colours), and brush the carriage under the ink tray. Worked for me.