Black specks down left center of page

[CraigD4]

I have specks appearing down the left center of the page on my LaserJet M401dn. (See below) 

I put in a new toner cartridge, and the problem was resolved for a while, but it came back exactly the same as before. I did the partial print test, and the specs are showing up before the fuser and are visible on the drum, but are not on the paper before it passes under the drum. The drum is getting cleaned properly on each pass. I have cleaned the drum with cotton balls and isopropyl alcohol, but it doesn't help. The specks seem to get worse the more toner that is on the page. However, even if I run a blank piece of paper through it, they still are there.

[Repairatrooper · Accepted solution]

Leaking toner, the problem is not the drum but one of the sealing blades.

[CraigD4]

Thanks Repairatrooper! I assume that this is inside the toner cartridge and nothing I can fix? Any idea what might cause this to happen to two cartridges in a row?

[Repairatrooper]

Are these original HP or remans? Depending on vendor we have seen failure rates as high as 80% for some reman cartridges. Media can sometimes cause problems as well, a bit of paper can get stuck between the drum and the toner receptacle and that allows toner to run down.

[CraigD4]

They are both original HP 80x cartridges. We do print a lot of #10 envelopes (about 100/week), but that's about the only thing unusual.