NOTES ON Laser Jet TONER REFILLING
After initial non-success with refilling a toner cartridge myself-- I've finally had some good results.
However, the toner generally doesn't automatically come with instructions, so you'll have to do a little hunting on the internet to find specific instructions for refilling your own brand of cartridge. Try searching Google using some key words like "toner refill instructions 'your brand of printer'". I eventually found the instructions for my Brother cartridge refill and overhaul- but it took a bit of hunting.
I have a Brother 1240 laser printer-- same as their newer 1440-- and previous troubles I had seemed to be fixed by using a can of compressed air and thoroughly spraying every bit of mechanismin the drum assembly I could access. This cleared out debrisand gunk that was preventing the new toner in the cartridge from applying properly. Simply following the toner refill instructions was not enough. And this was quite a fair amount of work taking the cartridge apart and refilling it. Also know that I have occasionallycleaned the drum itself when prints showed excess toner spotting my prints. (The drum is the very shiny green or blue colored electrostatic roller on the inside of the cart, accessible by a little poking around or by removing the toner cartridge portion if it is separate from the drum.) On both the Brother and a previous HP laser jet, I carefully and gently wiped excess toner off with a paper towel and denatured alcohol. This is a fragile part of the cartridge, so don't rub hard or use anything that would cause abrasion to this roller.
On the first and some subsequent refills, one might try simply opening the toner refill hole plug and putting in toner rather than taking the whole unit apart. This can be messy (although toner is dry stuff, it can go everywhere), so do it in the sink or outside first time.
Factory toner carts work perfectly, but alas, they are WAY overpriced. A total bogus rip-off. If you can find a reconditioned cart for your LaserJet, try it and see. I alwayshad good luck with HP Laser jet reconditioned carts. But if you are willing to try to actually replace the toner yourself, like ink jet refills- you will save a substantial amount. Again, this seems like a relatively simple operation that is just scares off people who think machines are too complicated to fix themselves. Click your amygdala forward, get a little toner on your fingers, and save hundreds of dollars.