I've got LaserJet P1005 that needs to have its print heads cleaned. hplip is installed with the gui but I don't find an option to clean the print heads. I'm on 12.04 64bit.
In most cases I might say that this is a feature omission, but in this case, because we're dealing with a LaserJet, I think it's just not a feature the hardware has.
Laser printers don't have "print heads". A laser etches into a drum covered in ink, toner tones things (alright, I'm a little sketchy on how they work exactly) and a static charge applies all of that to paper.
If you've got a mucky print, there are things you can clean but it's very different lingo from inkjet printers. And it's all manual work.