AL-1631 TONER LEAKING

I had same problem for 6 months. Water didn't run on desk, so my unit WAS level. So, I just pulled out toner & drum and vacuumed up & sprayed air everywhere to clean up, then I made sure everything was tight (including side door where the little wire thing you have to clean occasionally with little green plastic square (supplied w\copier). That piece on door needed to be up and as far back as it can go (It does move slightly in and out - make sure it is IN). I then changed the drum (put same cartridge back) - only this time I made sure everything was really in place tightly. Not sure which fix did the trick, but it stopped leaking, and I've since copied over 400 pages since then and also had to change the cartridge after about 100 pages.
PS I also vacuumed underside the copier unit with tray out, and inside the paper tray as well. I've unsuccessfully cleaned everything up like this before, but 1st time I've changed drum, and 1st time I made sure EVERYTHING was tightly in it's place. Let you know if it starts to leak again. Hope this is helpful to someone out there.
Shari.
PPS. I am NOT using OEM drums or cartridges, but clearly THAT was NOT MY problem

The one thing that will cause that, and has been something I have seen more than once. Make sure the machine front to back, is the machine sitting level? Take a line level and place it on the document glass front to back and see if the machine is level.
What happens is the toner and developer work to one end of the cartridge and it overwhelms that end. The other problem, is the cartridges being stored on end and not flat.
The ink then is all on one side and will not be able to stay in the cartridge when run..