C20 Print Quality Issue

[habik]

Have a constant dirt on prints, as if transfer belt is not cleaning properly. However it does clean properly. All IU drums are pristine clean. suspecting HV unit or incorrect bias on 2nd transfer.

see attached pdf.bizhub_C20_120907112206_0001.pdf

[Zeldaman]

Hi there!
What the F... is this? Had a similar problem on a C-35, but not so heavy. 1. thing was another PCU,Bk, no way. Next thing was to check all contacts (ITB,2nd Troller...), cleaning & adjusting them, problem gone.
Greetings...

[habik]

Hi there!
What the F... is this? Had a similar problem on a C-35, but not so heavy. 1. thing was another PCU,Bk, no way. Next thing was to check all contacts (ITB,2nd Troller...), cleaning & adjusting them, problem gone.
Greetings...

Yeah thanks, that was what I though is going to be, just did overhaul of ITB prior to your post, pulled the contacts on 2nd transfer to unbeareable sight almost a breaking point so contact is proper. This is the 2nd time i did it and yet it improves a bit but the sides are getting still dirty, then it evetually comes back to full page.

wonder if the AIDC is doing a good job.

[habik]

Found one dead Bk IU, swapped chips, Changed IU BK. Problem Disappeared right away!...what a pig.

[blackcat4866]

So you must have had two interacting problems. The ITB transfer contacts, and the black IU.

... and the cyan sprinkles went away also? I would have suspected the cyan IU also. =^..^=

[Hansoon]

Found one dead Bk IU

"Dead" defines as what?

Hans

[EarthKmTech]

that print sample is a common problem on c20's.


Its the black IU, and you will not see the defect by turning it by hand either.

[habik]

"Dead" defines as what?Hans

Dead as IU has run its life on 1 chip. Yet the quality was still good. So officially dead, yet usable for experiment or worst case scenarios. like this time.

[habik]

that print sample is a common problem on c20's.


Its the black IU, and you will not see the defect by turning it by hand either.

Thanks for that

Have you had any of the IU's apart ...I suspect the dev. roller is maggled up. as machine was not used much, and I think humidity is the factor that kills it. Plus customers soft touch and voila 10k on the clock and already new fuser and now even IUs Bk and C to follow.

[habik]

So you must have had two interacting problems. The ITB transfer contacts, and the black IU.

... and the cyan sprinkles went away also? I would have suspected the cyan IU also. =^..^=

On the first test pages it was without Cyan spots, now the starting to appear. after 30 pages since I changed the Bk IU...

Machine has been flashed with latest FW's . ONE THING REMAINS..FULL DISASSEMBLY AND THEN ASSEMBLY.