Need help on banding (F570)

[pond79]

I have the banding problem on F570. First the banding suddenly appeared all over the prints, the lines are perpendicular to the feeding direction. So the steel belt motor and the bearings in sub-scanning unit were replaced.

The banding was mostly gone but there is still a small area of it left that cannot seem to be got rid of. The area starts quite exactly 1.5 inch from the leading edge of the paper, and is 0.5cm wide (3-4 lines). What we’ve tried so far are:

- Replaced sub-scanning bearings and steel belt motor

- Replaced the steel belt, adjusting the tension.

- Replaced the LDD23, AOM driver

- Replaced RAM on image box

- Grounding is ok.

The lines are still there. It has been 2 weeks and I already had two teams of technicians working on it yet cannot seem to figure where the problem lies. Please help.

[yustas]

1. Check Belt, flat 329D1057346
2. Check a quality of all bearing in paper advance unit.
3. Check rollers also.

[pond79]

Thank you very much. I will ask the tech to look into it and will post the update.

[pond79]

Hello Yutas, I've replaced the advanced unit assembly with the new one from Japan. The problem was totally gone for 10 days and now it comes back.

This time it appears on many parts of the print, very obvious on light color area, merely invisible on very dark and very bright area.
I've tighten up the steel belt and it has become much less obvious by looking by the bare eyes. But it's definitely still there.

Do you think there's some other underlying issue beside the sub-scanning unit that causes the problem to recur?
Or this is an unfortunate new separated issue?

I've attached a new image (before.jpg) and the ones after adjusting the steel belt tension here (after*.jpg).

[pond79]

More scanned prints.

[yustas]

I heard you have found the cause of the issue?

[pond79]

Yes, the recurred banding was actually a separated problem. It came from the AOM driver.
After I've swapped the AOM driver, the problem is gone.

Thank you