C452 K void

[allan]

Had to change a K drum out on a C452 at a 100K well it needed the color. The yield should be around 300K for a working machine. In this case stabilization will eat away at some M's . The volume is very low but we are covered by minimum billing so i could afford to change out the drum.

The drum surface was even but looked a bit rough like the brushed stainless steel you find on elevators.
Reason i changed it was due to a void in the center of the the drum across the surface about two thirds of the length of the print area.
Any body know why this could be? The OPC is not scratched or warn thru.
The charge unit looked clean enough.

[blackcat4866]

I have a guess for you. Part of this is the reason why KM counts both images and rotations.

I believe that the OPC drums have some sort of clear coating on them. The friction from the blade cleaning the surface very gradually wears through this clear coating. When that coating is gone toner starts to adhere to the surface, usually in teardrop shapes, which can eventually extend into rotational lines.

On a few occasions when the toner buildup was not very bad, I have used paraffin lamp oil to clean off the toner buildup. Within a very short period of time the toner will adhere again in the same places. For the most part I don't bother trying to scrub those drums clean anymore. =^..^=

[EarthKmTech]

I've also experienced this on very low volume c452's. I've also had the black drum cleaning blade fail in such machines too with and without the drum looking like a vinyl record.

It might be a hot climate thing but in addition to the above I also used to get the dev unit mylars wrapping around the drum & destroying everything in the machine. I'm very critical of the 612 dev units, if there's the slightest concern with them I replace them with the drum 90% of the time - they are crap. We don't have many of these machines left anymore, the 4 series seem to be a massive improvement on these. 711 drums and devs last life and I've only had them fail once out of hundreds of machines in the area i look after.