1051 with Background on prints

[NMEngineer]

Hello there

Just wondering if anyone has any ideas on a problem I'm getting on a 1051, basically I was called in for background on prints which I thought was due to an insulated dev mix because of low toner coverage jobs so I replaced the dev and clened every component on the process unit aswell as setting all software dipswitches to factory settings as there were quite a few density settings that had been played around with by previous engineers and then I run through drum perculiarity adjustemens and when testing everything was ok but I then got a recall for the same problem the next day.

I decided to order a dev unit/dev mix, drum, and charge unit as these parts were well over life at 10 million prints (the drum had done 600K) along with a toner control sensor board as maximum density settings had been very low over the last few services so wanted to rule everthing out.

I then came back to fit these parts and when I checked max density it was around the 100 value rather than it being as low as 16 and all seemed good with perfect print quality but gradually after about 200 sheets of A3 the background came back and the only way I can get rid of it is by increasing the charge potential an extra 50V with dip SW 7-2 and 7-3 but there is obviously not quite right.

any suggestions would be greatly appriciated

NMEngineer

[pepper38_cnd]

I don't know if this will help but I had what sounds like the exact same problem on a Di850 not the same but close enough. Dev , Drum Charge full Pm evtried an etire drum cariage from another machine stil backgrounding. Today I change the entire drum shaft assy with the bearings and grounding collar and ground strap. That seemed to stop it.

[JustManuals]

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[Mick01]

Hi,
I had a similar issue escalated to me a couple of months ago. It was on a bizhub pro951 but is basically the same machine.
when i looked at the management list the machine had a lot of C-2809 errors. The funny thing is that the machine was not shutting down with this error.
The drum potential sensor was replaced which resolved the problem.
Check your machine for these errors and try replacing the drum potential sensor.
Hope this helps

[NMEngineer]

Thanks verymuch for your input guys, I was leaning towards both of those ideas as that’sall that’s left though I would have expected very erratic image behavior onhalf tones if there was a drum earth fault but it’s not the case with perfectimage quality.

There are no errors in the management list related to potential errors and it completesevery time when running adjustment, I'm just wondering if there is some sort oftolerance problem there and somehow the sensing has degraded (usually potentialsensors either work or they don’t in which case I'd get an error code)

cheers