Oh cheers, I've got an HP 1300 that's just turned 3 years old!
This doesn't sound like toner unless you're using cheap imitation or refilled jobs.*
I have some suggestions - and unfortunately I'm going by memory (I've used 13 lasers since the 80s):
1] the drum is on the way out along with the contents of your wallet
2] there's a doohicky called a corona wire which might be dirty
3] if the fuzzyness is patchy it might only be dirty rollers and/or drum
4] the cartridge has mechanicals in it, they could have cack in 'em.
What you need to do is hope that it's number 4. All the others mean you taking a risk attempting to sort it out yourself or taking the plunge and getting a repair man in. When we had machines like Apple's Laserwriter II it was easy for their owners. Now every manufacturer crams it all into solid-state plastic it's not so easy, hence the repair man.
Cheap carts and refillable carts don't save money or the environment, you just use more of them, spend more money on 'em, they shorten the laser's lifespan and increase landfill/recycling use. A bit like my personal view of a certain multinational fast-food chain.