HP 9500hdn unwanted marks

[monitor1]

My HP 9500hdn produces superb print quality but has in addition some  unwanted  marks as shown below.  Even after a number of prints the marks are still present but they vary with intensity but don't disappear.

I removed the image transfer belt assembly and the images below show the toner on the surface.

I cleaned the toner off the belt,  ensured the transfer cleaner was not clogged and re-assembled. Even on the first print the markings were identical to when a number of copies had been produced. The blue on the second image is toner and not a reflection. 

It seems unwanted toner is being applied to the transfer belt or the transfer cleaner is not cleaning the belt. I initially thought the latter but if the problem occurs on the first print after cleaning ththere should be no toner to remove.

A mystery to me but i hope there is some genius out there that has the answer.

It seems a pity to scrap the printer as it produces such great quality.

[Repairatrooper]

What is the life status on supplies like drum units? Have you referred to the service manual and the image quality trouble shooting contained there?

[monitor1]

Thanks for your speedy reply.

The Image drum status are:

Black             19%

Cayan            25%

Magenta      82%

Yellow           27%

The red drum has been re-chipped.

I have been through the service manual trying to find a clue to the problem and the image quality trouble shooting guide didn't seem to cover my issue.

This morning before switching the printer on I cleaned the image transfer belt. When it had gone through its set-up and before doing any printing i removed the transfer belt assembly and the belt had toner on it; see image.

So, it looks like the transfer cleaner isn't doing its job. I have two transfer cleaners and both produce the same result.

I printed off the menu map and the heading on pages 1&2 is still visible on page s 3-7 but gradually  fading. See image.

As both image cleaners seem not to be working correctly it appears to be an issue within the printer. How can i check that the wiper blade is actually contacting the drum?

[monitor1]

Good progress today.

I determined that the wiper blade was not being forced hard enough against the belt but couldn't find a means by which this could be adjusted. to close the gap.

I dismantled the transfer cleaner but again there was no simple solution. However, i eventually found a way by enlarging some attachment holes and pivoting the plastic cover away from the wiper blade. The blade is pressed towards the belt by springs and hence increased contact was effected.

I just need to check that i'm not damaging the belt but so far so good.

Thanks for your involvement.