LaserJet Pro 400 Color M475dn printing vertical bar distortion

[MoranJ2000]

Hello.

I've got a LaserJet Pro 400 Color M475dn that is consistently printing a vertical bar distortion on every page, including test pages from the unit's built-in diagnostics and reporting menus. The distortion appears about an inch from the left margin and is about a half-inch wide.

This occurs when printing mono or color, so it doesn't appear to have anything to do with any of the four toner units. It was suggested that I replace the fuser, which I did, but the problem persists.

At this point I'm not really sure where else this issue would be coming from, but I know it's coming from somewhere.

Any suggestions or advice would be greatly appreciated. Thanks!

[Valsimot]

Remove all toner cartridges and check the bottom of each cartridge (green drum) do you see anything that can cause your defect.

[Repairatrooper]

Can you post a sample, it could be an issue with the transfer belt and not the fuser. As suggested remove the cartridges and then look at the mylar belt under the cartridges in the cavity. A small piece of paper from a jam can get stuck in the belt and allow waste toner to spill out causing a vertical defect. DO NOT touch the belt with bare fingers, the oils from your hands will cause print defects.

[MoranJ2000]

Thank you for the replies.

I've included samples here, both pages generated from within the printer menus. I see now that my initial estimate of size and location were a little off, but you can see the vertical distortion is consistent across pages, be they mono or color.

I've previously checked the exposed surface of the toner units and see nothing that would account for this. 

This printer is in a remote office that I visit infrequently, so I haven't had a chance to examine the transfer belt, but I will do that today and report back.

Assuming I find something with the transfer belt, is it practical and cost-effective to repair or replace this?