PRESS 1052 line

**blackcat4866** · 04-27-2015

Originally Posted by Mick01

Hi,
I would check the earthing of the fur brush inside the cleaning unit. I have had issues on the previous models where the shaft needs to be cleaned that drives the fur brush roller that caused similar problems.
hope this helps.

Thanks Mick. I changed the fur brush recently, but cannot remember exactly what the grounding looked like. Do you know how this translates into the 32mm interval from the leading edge? A reasonable guess might be that the discharge during a previous cleaned image cycles around to overlay the next page ...

On recollection, there is a roll pin drive at the rear. And at the front a white plastic bearing holder, felt seal, bearing, gear, and clip. If there is a ground contact, it must a spring clip in the front or rear imaging drawer frame. There was no black grease that I can recall seeing. I'll check that. =^..^=

**Mick01** · 04-27-2015

Hi,
The earthing is through the rear shaft bearing. The drive shaft gets dirty (and even wears where it goes through the bearing). I recommend every time the fur brush roller gets replaced that the shaft is pulled out, inspected and cleaned. I am unsure about the process at the 32mm lead edge interval, I can only assume that with the increased resistance on the roller you are getting drum neutralising issues. sorry my explanation is a bit vague, I specialise on our colour devices normally and dont get involved much with B&W problems.

Again hope this helps.

**blackcat4866** · 04-29-2015

OK, so here are my observations.

Primary: There was some light toner dusting on both sides of the grid, and light ozone coating on the housing. Replaced primary wires and grid.

Cleaning Unit: Like most rolling ground contacts you don't see a steady reading. When I started I found:
0.02 Ω ground to inner roller
0.55 Ω ground to the brush
After the addition of conductive grease and a few shims I got:
0.02 Ω ground to the inner roller
0.06 Ω ground to the brush

Transfer Unit:
I think I found something here:
3.0 Ω ground to the driven roller
2.0 Ω ground to the transfer roller
0.6 Ω ground to the belt idler
After the addition of conductive grease and a few shims I got:
0.06 Ω ground to the driven roller
0.6 Ω ground to transfer roller
0.5 Ω ground to belt idler

There was noticeable toner dusting on the bottom of the drum claw guide (which I had cleaned only a few days before). My theory is that is where the image is getting smudged: pre-fusing. It only seems to occur on the 2nd side printed (or the first side image of the originals), and now can be seen on every page of a set (naturally in the samples only. I still can't get it to present for me).
Ordinarily I shun the shotgun approach to troubleshooting, but I'm getting tired of this machine kicking my ass. And it won't present the symptom for me anyway. Time will tell.

Thanks for the help. =^..^=

**blackcat4866** · 04-30-2015

Callback again, but this time the lines are considerable more faint. The drum claw guide remained clean.

I thought I'd take a different approach today. Since it's affecting duplex copying/printing, I thought perhaps I might find some unfused toner dumped in the inverter path, and getting picked up while inverting. The inverter was packed with paper dust, and a dozen shreds of paper from previous jams, but no toner. Some of it is fairly easy to clean, but the area under the fuser is inaccessible without a total teardown. As a compromise I took a heavy transparency, wrapped it with a stretch-N-dust, and rolled it through the inverter path. The rollers and sensors cleaned up easily.

Not really expecting to see the problem I ran 120 duplex. Toward the end of the test I did start to see the faintest hint of the line.

My plan "B" for today was to swap the transfer belt assy with the sister machine across the isleway to see if I can move the problem. After the swap both machines ran 300 duplex without the symptom. We'll know for sure tomorrow, when they will print another 30K. If it's truly gone, I'll replace the bad transfer belt assy. I would like to know exactly what was causing it, but enough is enough. =^..^=

**blackcat4866** · 05-05-2015

It was the plan "B" that bore fruit. I created the issue on the sister machine, so the transfer belt assy is part of the problem. It took 5 days for it to come back to the original machine. I interpret that to mean that the transfer cleaning unit is suspect also.

As a plan "C" I see that there are HVT contacts to the transfer cleaning unit. Maybe HVT next? =^..^=

**blackcat4866** · 05-07-2015

Transfer belt assy didn't help. Transfer cleaning assy on order. It seems to have spread like a virus to the other machine now.

Customer is making threats now. That's always so helpful. =^..^=

**allan** · 05-07-2015

Are you sticking to PM scheduled on those machines?
Maybe time for some new units?

**blackcat4866** · 05-08-2015

2.3M and 2.7M respectively as of today. They've had all the scheduled, recommended by KM maintenance. The new transfer belt assy made it more faint but not gone. I've got the transfer belt cleaner assemblies on the way.

I have a hard time reconciling that the machine can run from 1000 to 5000 without a single flaw before commencing the line problem.

Ideas that I have been toying with:
Transfer belt cleaner drive? There is no evidence of waste buildup in the cleaning unit.
HVT? Perhaps some kind of a spike in the cleaner bias? But how does that fit with occurring exactly 32mm from the leading edge?
How about transfer timing? Perhaps there is some residual image left on the belt that reprints on the next rotation. It does not look like a belt cleaning problem though. The "line" is not affected by positioning of large blocks of fill. Even where there is no fill in line, the "line" remains.

Ah well, I'll stumble on. =^..^=

**allan** · 05-08-2015

That would leave you with the components that creates image. Like charge and dev bias. But in the same place every time? could it be a power or an EMI problem?