Weird density issue c258

[nitro912gr]

yeah I can't catch a breath lately with my c258, after spending a good amount of money to service it and when I finally found that my latest problems where my transfer belt, today I met a brand new problem!
Maybe I should have bought a 250i instead of servicing it... how worst it could be with those eco toners anyway?

Well here is the thing.
I have new drums on the machine and the transferbelt although damaged and give lines in the short edge of A3 (because of heavy stock I was passing) is working fine and is relatively new.
The drums are all K but changed chip and that plastic thing and all works fine when I print test CMYK colors (although not very fine in the K see attachment).

The main problem is when I try to print colors like mint or a peach tint, the uniformity is going bananas, I repeat, prints on CMYK at various densities, through PCL or PS driver, are all fine in density.
See the attachment for the other colors tho... weird thing. It wasn't there I can confirm from a preview print job that I happened to have, the mint was printing great, it is my shops main color after all I print it all the time.

Now the thing is those 2 have not any K in them to suspect the K drum is the culprit that show a similar pattern for some reason (although I don't understand why the K behaves like this, it is not noticeable as much as is the color ones).

Tests I did, changed the CMY with each other to see if there is any problem with Y that seems to misbehave. Nothing same results.
Stopped the machine mid print and got the drums out to check on them, the toner seems evenly spread with nothing that resamples the problem on paper.
Also checked the transfer belt but this is hard to see and didn't want to get it out because it is getting late and I'm tired, bad things happen when you tear down stuff when you are about to go home.

Any idea? Did the transfer belt show me the middle finger already? Is it possible it is the developer? seems weird to be the developer since the CMY come out fine.

S25C-924031920450.pdfS25C-924031920271.pdfS25C-924031920270.pdf

[Synthohol]

i didnt see you mention it but what adjustments have been performed so far?

[nitro912gr]

the automatics only, did I had to do anything manually through the service menu after the installation of the drums? This rings a bell but I don't recall what I did the last time, what did I forgot?

[Synthohol]

background data reset and stabilize then all gradations.

[Markks]

how old is the 2nd transfer roller?

[JasonSBE]

Definitely run background reset and gradation. May want to clean the IDC sensors as well.

[nitro912gr]

Honestly I feel stupid now for not even doing the IDC sensors calibration, I will do everything asap.

Second transfer roller is brand new, one of the first things we changed before we conclude on the damaged transfer belt.

I have some time today I will do all the adjustments mentioned.

Thank you!

edit: I just did the resets/adjustments but still get this weird print, just to make sure the background reset is the reset it mentions in "initialization + image stabilization" in stabilizer menu right?

[Synthohol]

yes

[nitro912gr]

unfortunately nothing changed after doing everything suggested.

Could it be a dying yellow developer? Should I give it some time to work as the newer toners come with developer refill inside the toner to prolong their life?