I was skeptical that I needed a new toner collection unit, but I have 2 HP printers of the same model that uses them. Both printers were better after putting in new TCUs. One printer wouldn't print at all (because it wanted a new TCU) and I was cursing HP - there is really no reason you can't clean the old one, from my point of view. Anyway, the one printer worked again. So, since the TCUs came in a pack of 2, I put the 2nd one in my other printer, which made it print a little cleaner (I also have an issue with the ITB Intermediate Transfer Belt, which caused some streak/marks on the edge of printed pages). I still need a new ITB, but printing was a bit better with new TCU. Small price to pay for improved performance.