C6500 - Shaded stripe, fuser?

[dagoof]

Got a shaded stripe (about 20mm thick) running lengthways up the middle of the the sheet on a c6500, it looks like it's in K, it's quite faint but noticable - new corona & drum and ran initial setup procedure but that didn't help. Thought it may be a transfer roller, so swapped over the transfer unit from another machine but it's still there. Eventually tried putting the fuser into another machine and the stripe was still there on the other machine, so guessing it's down to the fuser - but the problem only manifests itself in black (test pattern #53).

Any suggestions?

[Mick01]

Re: C6500 - Shaded stripe, fuser?

Hi,
What is the thickness and size of the paper.
The reason I ask is that there is a limitation with this model where thick paper as it enters the fusing unit causes a shudder in the transfer belt unit. This in turn causes the black transfer roller to shudder which causes the mark. The only workaround for this is to set "Thick Paper Black Mode" to on in Utility-User Settings-Common Settings. This engages all the colour transfer rollers whilst printing black only to support the transfer belt better. This minimises but not resolves the problem.
If the mark is appearing on light weight stocks then it could be the following in the fusing unit. Fusing entrance sensor, Fusing entrance sensor actuator, one way drive gears in the fusing unit.
Hope this helps.

[dagoof]

Re: C6500 - Shaded stripe, fuser?

Yes, that's very helpful - thanks Mick, it was indeed thick stock, so I'll try that. That said, swapping over the transfer unit, the mark does seem to have more or less worked it's way out, so maybe old transfer rollers weren't helping.

[dagoof]

Re: C6500 - Shaded stripe, fuser?

Funnily enough, just been told the line's working it's way back...and the 'thick paper' setting was already on

[Mick01]

Re: C6500 - Shaded stripe, fuser?

As I mentioned if the band does not appear on thinner stock it is limitation of the machine unfortunately. Changing to a line screen with a low screen frequency also helps sometimes but depends on the file printing.

[dagoof]

Re: C6500 - Shaded stripe, fuser?

Thanks Mick, I can appreciate that. It's something that only developed recently though - and comes and goes, so I'm hoping there's a root cause that can be addressed other than machine limitation. Will try a different screen too though.