C550 Black image - low density

[VZDPrinters]

When we print a halftone test patern - solid black the image comes out streaky like example.

I have done a TCR supply, also set the fusing temp up by +5, and transport speed -5. All results are no good.

The machine has a new K IU in.

Thanks in advance.

[Gaffers01]

Probably the transfer belt.

[VZDPrinters]

We played around with the machine, did grayscale adjustments and ran a Few TCR manual feeds. It is better but problem persits.

I also read on another post that the contacts of the IU is a problem on the C550, I have made sure they connect tightly. And looks like its better.

Would this problem be visible on CMY if it as the transfer belt or only on black ?

Thanks

[tech51]

Have you tried cleaning the windows on the write unit?
We have found that over time the windows get fogged up and the cleaner wand doesnt shift the dirt.
The answer is to remove the write unit and clean the window glass with your favourite glass cleaner, re fit the unit and set up gradation etc.
Hope this helps....

[EarthKmTech]

the cleaner wand is utterly useless on the c451/452 series. The only way to make it clean properly is to remove the imaging unit and apply some LIGHT pressure to the pad with a finger through the slot under the iu while you pull it back and push it in. For stubborn marks I dampen the pad with rubber roller restorer (gods gift to technicians that cleans anything and everything, awesomely)

I've no idea what they were thinking when they designed this, it doesnt even travel straight or on top of the glass if you do it the way they intended.

I have never needed to remove the PH to achieve crystal clear glass windows. Even if the K-iu dumps, i use the long straw attachment on my vacuum to clean it all out before cleaning the windows.

[VZDPrinters]

We have solved the problem. :D

It was the black image unit. This was/is a new unit, but clearly it is a faulty one. We have put back the old unit and printing is better but will need to change this ons almost over life cycle.

Thanks for al the help.