hp 8550dn

[ATSBMCO]

I have a 8550dn that prints feint for about the first 15mm of the leading edge on each document but the rest of each page is fine.

The image on the transfer drum is ok throughout.

It has had a new drum and transfer kit

[LaserSharp]

Facing the into the machine looking back towards the fuser there is a small spring attached to an arm along the right-side of the printer.
This arm often cracks and/or breaks in these units, the spring may be hanging there not attached to anything or could be missing entirely.

[ATSBMCO]

I know what you mean, this is at the rear next to the roller, I have replaced this with a new kit and still the fault persists.

[LaserSharp]

While a much less often seen problem anouther does occur to me.

Check the sides of the transfer drum assembly, on the left hand side there should be a small tabb that sticks out about 1/4 inch with 4 or 5 teeth (like gear teeth) on one edge, I've seen this broken off.

also check the plate that has the guides for the transfer drum formed into them, the square plate that surrounds the drive shaft is made of plastic and can crack or break causing the drum to sit improperly in the machine.
Replacements are available that are made of metal. The part is a bit hard to find in that it's hidden in a "kit" of parts that are meant to solve or prevent a couple other problems as well.

RG9-1495-000CNPEP (Product Enhancement Package) kit - Contains all service parts including transfer guide and instrucions for installation of this kit

If the machine is'nt to far from you I would do a visual check for damage there. In the meantime I will see if I can dig out my manual for the unit and see what it might say.

IF the image looks good and strong on the transffer drum, either the drum is not moving down into place properly or you haveing a transfer voltage issue, my exp with these machines would lean towards a mechanical issue.

[ATSBMCO]

I stopped the print cycle mid way and the image on the transfer drum is spot on, no fault whats so ever.

The printer is in our work shop, and I cannot see any broken or cracked items.

With our experience on HP I think I may have a faulty HVT but I dont have another to check.

I appreciate your help.