Bizhub Press C7000 2nd transfer drop out.

[wjurls]

Hey guys, having trouble with a C7000 with a sudden onset, and consistent issue with the 2nd transfer. On plain 11x17 the image is complete but the overall transfer appears poor.
49540

With heavy coated stock the second transfer drop out completely. About 4 inches from lead edge and again from about 4 1/2 inches from the trail edge all the way to the end.

49541

I replaced the 2nd transfer roller and neutralizer, cleaned all contacts to no avail.

Image that's missing from page is found in full density on intermediate transfer belt.

Any ideas?

[tsbservice]

Not familiar with this model but definitely second transfer issue if image is good on belt. Door is closed enough?

[wjurls]

Door doesn't seem to be an issue. I was thinking HV unit but the fact that it's always in the same area has me thinking a mechanical issue??

[Toxic]

I would check 2nd transfer roller pressure mechanism, pressure release motor, cam, pressure arm...
Try to change pressure and see is there some difference in transfer.

[wjurls]

I would check 2nd transfer roller pressure mechanism, pressure release motor, cam, pressure arm...
Try to change pressure and see is there some difference in transfer.

Thanks, Had customer change from auto to low pressure and same result. Might have to try replacing the HV2 board.

[tulintron]

If I print 10 pages of the same file, does the defect always happen in the same place?


I believe I'm a mechanic, but...


On the 2nd bottom transfer roller there will be no voltage. The voltage on it is 0v. On the 2nd transfer roll above the voltage is negative.


But how would the HV2 always fail in the same place in the image?


On the 2nd top transfer roller, there is a black electrical contact that over time will need to be replaced. I've seen mounting this roller wrong. It may be inverted, causing wear on the 2nd upper transfer electrical contact.

49547

[Toxic]

Good point Tulintron, worth checking that.
You mean this one?

49548

[tulintron]

Good point Tulintron, worth checking that.
You mean this one?

49548Perfect Toxic! On target.

[wjurls]

If I print 10 pages of the same file, does the defect always happen in the same place?


I believe I'm a mechanic, but...


On the 2nd bottom transfer roller there will be no voltage. The voltage on it is 0v. On the 2nd transfer roll above the voltage is negative.


But how would the HV2 always fail in the same place in the image?


On the 2nd top transfer roller, there is a black electrical contact that over time will need to be replaced. I've seen mounting this roller wrong. It may be inverted, causing wear on the 2nd upper transfer electrical contact.

49547


The image dropout will be generally in the same place but might fluctuate around by about 10 mm or so. I have the same hesitation on the HV2 being issue due to it not being sporadic.
Good tip on the upper 2nd transfer roller contact. I will take a closer look at that. I wish I had a spare unit to try it with.

[Toxic]

If i remember good this contact bugs me before on C6501, had internal resistance over 100 ohms.
You can dissasembly it, i think there is 2 metal plates inside making contact betwean and for some reason resistance was high.

[tulintron]

If i remember good this contact bugs me before on C6501, had internal resistance over 100 ohms.
You can dissasembly it, i think there is 2 metal plates inside making contact betwean and for some reason resistance was high.Resistance increases because the 2nd transfer up roller is mounted inverted.

As a result, the moving end of the roller, in contact with the electrical terminal, generated physical wear and gradually increased resistance.

[wjurls]

I would check 2nd transfer roller pressure mechanism, pressure release motor, cam, pressure arm...
Try to change pressure and see is there some difference in transfer.

The winner is.... Toxic! Total rookie oversight on my part. Upon closer observation this morning I found the lift gearing for the 2nd trans roller to have a dead spot. Ordering new motor and gears.

Thanks everyone for the help. Now on to a C8000 with a nagging C-2235 code!!

[Toxic]

I am glad you solved it and thanks for feedback and solution.