C1860FW Magenta Vertical Line on Left Edge

[MooPhotographic]

Only happens when magenta toner is used.

Really hoping someone has a simple solution to this. I'm getting this line on the left on every print that uses the Magenta toner. Here's what I've determined so far:

No, it's not Samsung brand toner and I don't believe that's the issue. CY and K toner cartridges are not having this problem. 

I requested a replacement set of toner. The second set had the same result. Maybe slightly less but still there. 

When I put in the old Magenta toner (which is now empty) it stops. No brainer, I know, but I did check.

The drum does not appear to have any defects on it, on either the first cartridge or the replacement they just sent.

I don't see anything built up on the rear feed roller (back door).

Does anyone have any other ideas? I would have blamed the cartridge but, I've gotten a replacement and the same thing happens. I suppose it could be two bad magenta toner cartridges but that thought process seems suspect. Before I return them both and try this again with another brand, I'd like to make sure nothing else is going on. I appreciate any help you all can give!

[Repairatrooper]

Can you confirm that this is left edge and not leading edge? It would be rare to see this type of defect down one side happening only in one color except for a bad cartridge. Have you checked the transfer belt for any excess toner?

[MooPhotographic · Accepted solution]

Thanks for the response. It was not the leading edge - what you're looking at in the photo was a trimmed section of an 8.5 x 11" paper that I pulled out of the trash to compare the marks to subsequent prints. The magenta "stripe" is running along and off the far left edge of the paper if you were holding it after is was printed, to read. 

As of now, I've chalked it up to a bad toner cartridge. What I think happened was the first new cartridge that was installed had a bad wiper and it was leaving a stripe along the edge that wasn't getting cleaned off somewhere (where exactly, I don't know) inside the machine. When I installed the newer, replacement, magenta, some of that residual toner was still floating around on whatever it was collecting on so I was still getting the stripe. I blew out the inside with compressed air, ran a few more test prints, and it lightened then magically disappeared. All appears to be well and good for now.

Unless someone has another answer, I'm going with - aftermath of bad cartridge. Hopefully someone else sees this at some point and it helps!