Is this practice legit?

[jmaister]

swapping drums? As in CMYK interchangeable, but I'm seeing side effects.

Y got moved to K cuz k drum got a scratch, but then print outs get these smudges in around 38mm interval or full page bleed.

any ideas? If its legit, how do I explain the smudges?


thx

[Hemlock]

Possible that you marred something when swapping.

[jmaister]

i didnt do the swap lol, was trying to fix a issue created before me. now its sparkling clean.(i changed them back.)

[Hemlock]

Just guessing; if they were replaced at the different times, and tests/sims in tech mode were done properly, it could be that charge levels and dev bias levels are set for that particular drum. As drums age and the surface wears, these charge levels are constantly adjusted to achieve the best possible image. Swapping them without adjusting main charge, dev bias and other required fields could be the source of your problem. It would also explain why it all got better when everything was put back in place.

[blackcat4866]

Just to muddy the waters:
I agree with everything that Hemlock has said except that the repetitive image defect at 38mm intervals is the primary charge roller for that particular color, and is totally unrelated.

So, print each U089, gray test pattern in each color to identify the problem charge roller. Replace that charge roller, and perform a color calibration.

Just out of curiousity, what did you hope to achieve by swapping drums? It's a great diagnostic tool, but just shifts your quality issue from one color to another, fixing nothing in particular. =^..^=

[jmaister]

*chuckles.

I wouldnt, and I absolute agree with what's been said.

The 38mm smudge, after testing, charge roller is shot. That's not related as pointed out.

As to why for swapping, trying to hide a scratch and the kid just didnt know what he was doing.