Black Triangle Smudges on the Right Side of the Paper

[LHOwens]

When I print black and white as well as color, I have five black triangular smudges on the right side of my paper. This has been ongoing and not an issue with the toner cartridges, as I have gone through muliple black cartridges (HP certified) over the course of the year that this has been an issue. It has worsened over time.  I 've cleaned the transfer tray and print transfer roller and basically wiped everything that I can reach to be sure there is no loose toner anywhere. What else could this be? I would like to try to fix the issue myself if possible. I am not a technician or mechanic but am fairly good at following tutorials and directions. Any help you can provide will be greatly appreciated!

[Repairatrooper]

Most likely a delaminating fuser assembly. We find in our shop that this type of failure is fairly common on the left side on printers with 35K or more pages. The life rating of the fuser under ideal conditions is 50K. Ideal conditions is printing on standard plain paper and every job consisting of 3 pages. Consistently printing single page jobs can reduce the life of the fuser by up to 50%.