DP-C266 Quality problems on duplex prints (Second side)

**User Name** · 03-05-2015

Hey Everyone,

On the second side of any document there are smudges/shadows around the boarders of high fill areas. I had the opposite (missing fill in high fill areas) of this problem awhile back on the same machine and got some help with it.

Here's that thread:
lStrange quality issue on DPC 266

It's definitely still related to the charge in the STR. I tried changing the STR with one from a parts machine with less copies on it and no issues but this actually seemed to make the problem more pronounced. I left that unit in though because I'm certain the STR itself isn't the root of the problem and the customer's was pretty well worn. I adjusted F5-157 to different values and tested to see what effect it had and the HIGH setting takes care of the shadows but at the cost of the density of the high fill areas.

Here are some samples of the problem with F5-157 set to different values:
Attachment 28323
It's hard to see in the scan but hopefully it'll give you an idea of what the shadows look like. You can really see it around the black box in the top left on the first image. I had to darken the exposure for our scanner to pick up the shadows so it's all a bit darker than it is too the naked eye.

Here's the F5/F6 settings if those are any help: (F5-157 is HIGH now not MIN. Printed these before making that change)
F5 F6.pdf

The machine has about 500k pages through it with the original Transfer Belt still in it. Could that be throwing off the charge in the STR? Any ideas would be greatly appreciated. Thanks in advance!

**onetek** · 03-09-2015

I would try an IT belt and FTR kit. On those copiers, STR touble shows up more as voids . F1-38 will also show you transfer quality.

**User Name** · 03-11-2015

Originally Posted by onetek

I would try an IT belt and FTR kit. On those copiers, STR touble shows up more as voids . F1-38 will also show you transfer quality.

Thanks for the response!

I replaced all the parts in the 240k maintenance kit today and the problem is still there and possibly worse. Hard to say exactly because it does vary slightly and I only did a few tests. I'm going back probably tomorrow to disassemble the side-door with the STR unit and check all the connections and grounds. Hopefully that will make some difference. Other than that I'm out of ideas.

**onetek** · 03-12-2015

Did you try printing in monochrome or one color only to isolate this trouble some more? Transfer can only transfer what's on the belt. If your problem is more pronounced with new parts, or by changing transfer current, it means that that the smudges are already on the belt, so the trouble is upstream. How old are you devs and drums?
Th.

**User Name** · 03-12-2015

Originally Posted by onetek

Did you try printing in monochrome or one color only to isolate this trouble some more? Transfer can only transfer what's on the belt. If your problem is more pronounced with new parts, or by changing transfer current, it means that that the smudges are already on the belt, so the trouble is upstream. How old are you devs and drums?
Th.

Thanks again for the response!

I've tried B&W prints and it did it on that too. The shadows show up around any high-fill area. I don't feel like it's an issue with the transfer belt for this reason: simplex copies are perfectly fine, no issues at all and it's only the second-side of the duplex prints that have the issue. Upon more testing, I don't think the new parts made it worse. The problem just varies between jobs. If it was an issue with the belt, drums, or developers, I'd expect to see the problem on all copies and not only on the second-side of duplex copies. I could be wrong but my gut tells me something is up with the STR somehow. Especially since adjusting F5-157 changes the potency of the shadows. Seems like a charge issue to me. My thinking is that imagine is fine when on the transfer belt but then is messed up when pulled to the paper by the STR.

So, this morning I went back and checked all the contact points for the STR on the door and in the machine. I cleaned / adjusted everything and it all looks good but unfortunately it didn't help and the problem is still there. Not sure what to try next.

**onetek** · 03-13-2015

If single side copy is ok does not mean that 2 sided should be: I know that str voltage bias as well as a few other settings change.(because paper is dryer, static charged, inked on...).Is the problem only with black high fill areas? Color high fill?

**User Name** · 03-13-2015

Originally Posted by onetek

If single side copy is ok does not mean that 2 sided should be: I know that str voltage bias as well as a few other settings change.(because paper is dryer, static charged, inked on...).Is the problem only with black high fill areas? Color high fill?

It happens around both black and color high-fill areas.

**mojorolla** · 03-13-2015

Pulled my notes from a few years ago, dropped Panasonic almost 6 years ago, and I found 2 instances with duplex voids resolved by replacing the black DV unit. It does not make any sense, but that's what the notes say if it helps.

**onetek** · 03-16-2015

Again, to isolate further, you could print your samples and stop the copier right when second side is in front of it belt (by opening front door).Then, pull the it belt enough to rotate it and see if your high fills have clear edges on the belt before being transfered.

**Teddybrink** · 03-16-2015

Being that it's a 2 sided original, are sure your exposure setting is not too dark? It looks like it's showing print from the other side of the original