Xerox C75 Print Quality Advice...

[kdw75]

Recently I have been noticing a decline in print quality on uncoated sheets, such as Accent Opaque 60#. The best way to describe the issue is that it looks like it was run offset without enough pressure. The colors in photographs look splotchy and don't cover the sheet evenly. On coated sheets everything looks great. Not long ago we had the roller right before the fuser replaced, I think it is called the 2nd bypass roller. Could this be related to our problem? I haven't talked to Xerox yet.

I have tried swapping imaging units and it didn't help.

 

[jotterpinky]

This is what we usually refer to as mottle in our shop. The only way I've seen to get it cleared up is to have a technician come in and put in new developer. It might be you can narrow it down to one of the colors in particular such as reds or blues and then only change the appropriate developer color. In most cases our tech will end up changing all four to avoid having to come back again.

 

[kdw75]

This is what we usually refer to as mottle in our shop. The only way I've seen to get it cleared up is to have a technician come in and put in new developer. It might be you can narrow it down to one of the colors in particular such as reds or blues and then only change the appropriate developer color. In most cases our tech will end up changing all four to avoid having to come back again.

Thanks for the reply. We have had that problem, but that usually shows up regardless of the paper. This seems to be isolated to uncoated sheets that aren't perfectly smooth.

 

[jotterpinky]

it could very well be the roller you mentioned then. From my understanding (dont take this as gospel) this is the 2nd Transfer roller that transfers the toner from the belt to the sheet. When you go into the custom paper types and adjust the "image transfer" it's adjusting the bias between this and the sheet to "pull" more toner from the belt to the sheet. If you're getting transfer problems this might be a likely suspect. Have you tried making adjustments to "image transfer" and does it make it look better than it is currently?

 

[kdw75]

it could very well be the roller you mentioned then. From my understanding (dont take this as gospel) this is the 2nd Transfer roller that transfers the toner from the belt to the sheet. When you go into the custom paper types and adjust the "image transfer" it's adjusting the bias between this and the sheet to "pull" more toner from the belt to the sheet. If you're getting transfer problems this might be a likely suspect. Have you tried making adjustments to "image transfer" and does it make it look better than it is currently?

I have not tried adjusting this since the problem occurred. I had only tried this when I was having trouble with linen stocks a few months back.

 

[indy jones]

We have the Xerox J75 printer. Have you tried using SQIA software density uniformity adjustment?

 

[PlanetDave]

Check the Fuser

Check the Fuser

Check the Fuser

 

[kdw75]

Fuser didn't make a difference and the uniformity is good.

I tried adjusting the 2nd roll transfer setting, and none of them were good. I found that a -1 setting looked better for solids, while a -3 setting looked the best for screens, then on the other side of the duplexed sheet it needed different numbers.

It seems like since the tech replaced the belt and 2nd roll, things have gone down hill as far as image quality is concerned.

 

[Harley Dave]

Did this happen after running a longer run black only job? If you are running the Free Flow RIP try running black jobs in the "Fast Black" Mode our tech told us this "shuts off" the other colors of toner and developer so it doesnt get beat up. Seems to work for us

 

[kdw75]

It seems that it may be the paper at fault. I had been running a large job on International Paper's Williamsburg Plus 60#, and it seems that this paper is leaving some kind of residue on the transfer belt causing a weak image. The only way to recover after running, seems to be to run a bunch of solid sheets on some gloss paper.

The Williamsburg says right on it that it is for digital and offset use. Unfortunately I have a quarter million sheets of it that I have to finish running through our machine in the next few days.