hp 877dn black lines 2mm apart across entire page

[swfc tech]

hello i have an 877dn that is putting black lines across the enitre page perfectly 2mm apart i have factory reset updated fw to latest version replace the pcu i have contacted hp support who was of no help as usual telling us they have never seen anything like this and to start replacing parts and let the know what fixes it if anyone has seen this before please let me know

[tmw]

I can't say I've seen this before but it could be related to the formatter. It almost looks like an engine test printed over a normal page. The engine test is supposed to eliminate the formatter for testing. There could be some weird interplay between them.

[swfc tech]

according to hp if that was the issue it shouldn't be edge to edge full bleed we have replaced the developer unit and that seems to have resolved the issue i will follow up with the client in a couple of days to make sure