Gradual whole-page streaking on CP2025

[tendonut]

Fairly recently, after my wife decided to print to a bunch of envelopes, my CP2025n has been a total streaking mess. The first print is usually perfect, then each page after it gets progressively worse. I printed 10 pages at once to demonstrate the degration in quality.  If I give it a 30 minute break and print again, the cycle restarts and the first page is great again.

I'm trying to figure out what component is shot/needs cleaning. I am thinking the ITB, but I am hardly a printing expert. What does this look like?

(I have no idea why this forum is ignoring the orientation metadata of this picture, but whatever....)

The HP test sheet is the "first" page, and the middle page is "page 5", and the right page is page 10. 

[AlS77 · Accepted solution]

It looks like the black toner cartridge has gone bad. Try a new one and see what happens. Printing envelopes shouldn't have affected/caused this. Sometimes cartridges just go bad. Try stopping the printer in mid-print by opening the front cover when it is at it's worst and pull out the toner cartridges and look at the drums on the bottom side. You should see the same contamination on the bad ones.

[tendonut]

You are correct! The black cartridge was bad.

I actually had another black toner cartridge lying around (the only color I have an extra of).

I didn't want to open it yet, in case that wasn't the issue, so I tested it the way you suggested, and indeed there was residue on the black toner drum.

I replaced it and it was good to go. No more streaking. Now that this is resolved, I'll attempt to figure out why I get a perpetual paper jam when using the manual feed tray...Thanks!