The only vendor that sells bulk toner is AAAToner in CA that I can find. I've used them before with no known issues. There are plenty of places that sell the cartridge, but no idea whose toner is inside.
Before someone asks, I like the unit, I don't use is often, mostly for larger jobs of text...
I did open up the drum unit and cleaned it out including what appeared to be the 'blade' which didn't seem dirty. I did empty and clean out the reservoir area in the drum thou.
I then did some test prints and they are far better, but there is still a residue that gets worse towards the left...
I have a older Panny laser printer/scanner (MB-271). The drum is fairly new. I don't print often.
The cartridge ran out, I refilled it with toner that I bought 5/22. Is that considered too old?
The printer was printing fine. Now after filling it prints dark on one side, and gray on the other...