I have an old HP 2550 Ln laser printer which recently stopped printing AT ALL. It would simply spit out blank pages. After doing some digging I discovered that the likely cause was that the big wheel that cycles the four colors likely became misaligned. I suspected this because I heard the printer jam in a very gear mashing kind of way and because I could visibly tell that the cartridges were slightly misaligned when I opened the printer (and one side didn't line up with the guides).
So following the maintenance manual, I disassembled the printer and realigned the print carriage.
I also wiped down the toner cartridges with cloth and water b/c the yellow cartridge had managed to leak yellow toner all over everything.
Now I'm getting pages like this and I have no idea why:
I can confirm that there is a decent amount of toner in all of the colors.
The image is correct where the toner managed to stick, but it looks like the toner isn't sticking to most of the page.