Konica C253 , missing color only when printing

[wild140]

Replaced the black drum because of streaks on the old unit. Now when they print the black only in areas where there is a picture seems to be missing or very faint , text that is pure black looks good. If I copy from the platen the copies are perfect . Tried reloading drivers PCL and different driver UPD and different workstations all N/G . Best way for me to describe it is it seems the gray scales are off.
I put the old drum back in same result. I do not know if the issue was before I replaced the drum because I only saw the streaks on a black and white copy on first visit.BRWD46A6A5A8713_0000004607.pdfBRWD46A6A5A8713_0000004607.pdfBRWD46A6A5A8713_0000004607.pdf

See Attached

[Zesti]

Re: Konica C253 , missing color only when printing

Change Drum meaning changing IU????
Clean the laser glass below K IU with magic wand inside the front cover. Hope it will help.

[Terna247]

Re: Konica C253 , missing color only when printing

You could get to the corona blade and carefully clean it. Then run at least 10 copies to see if it helps. Sometimes this could be an exposed drum. Try changing the drum with the old again to confirm if it's coming from the drum.

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[Synthohol]

Re: Konica C253 , missing color only when printing

it would be most helpful seeing the 4 individual color gradation patterns from service mode.

[femaster]

Re: Konica C253 , missing color only when printing

Have you tried to run gradation adjustments? The solid black areas seem OK, it just seems the areas that need a lighter shading of black aren't getting enough. Clean the laser glass as someone else had suggested and then run the gradations adjustments as instructed in the service manual. See where you end up after that.

[nassor]

Re: Konica C253 , missing color only when printing

Do Initialize + stabilization
And gradation