Xerox 700 streaking, banding, large area coverage and light color

[veronika_zoobs]

Hello all,
lurker for a few months, thanks for all the information you've given me thus far!
I work for a plastic die-cut card company and we digitally print on two Xerox 700's.
Aside from plastic cards, we also run paper cards which include postcards and such.

We have a great deal of problems trying to print large coverage areas with light colors.
I already know that large coverage areas pose issues for digital machines (experience) but we get great coverage on 100% Cyan (0% MYK) it's a nice, even coat on the paper. Our issue is with light colors over a large area, you can see streaks all up and down the sheet.

From left to right, 4 sheets:
1. Original print (not copied or scanned)
2. PMS 326 (to see if any change)
3. PMS 325
4. Changed the Cyan up a little in percentage, still streaked

Machine is set to 257-300 gsm, coated, on 13x19 sheets of 120 lb gloss cover (326 gsm).
Our problem may be that the paper is too thick for the machine, so we ran the same color on thinner stock.

We changed our template around to be able to print on 12x18 sheets of 300gsm coated cover, which fits the specifications of the machine, and the print at PMS 325 came out as so:

Other than replacing the developer and drums, toner cartridges, resets and calibrations (ALL DONE!), is there anything ELSE we can do to minimize the streaking in light colors??

 

[Justin de Kruyf]

If you measure the distance between streaks (or between good, solid areas) and it turns out to be more or less uniform then it could be a roller that needs to be cleaned. Our 700 had a repeating pattern that looked similar to what you've got going on and there was residue on a roller that the technician almost missed because it was only visible when he shone a light down the length of the roller.

In the case of a dirty or worn roller, the distance between the marks will indicate which roller needs to be looked at. Because we've got a service contract I have no experience servicing this part of the machine myself so I couldn't tell you how to determine which roller it is.

 

[arossetti]

You should try some test patterns in other colors to see if this is a cyan issue or not.

Might try swapping a fuser, and have you changed the corotron? You said new developer but have you changed the housing? I'd say either a corotron or bad cyan housing.

EDIT: Of course now I'm confused which way these are running through the printer, I think what I thought was the process direction is not.

 

[Alith7]

is your text or solid line blurred in any way? It's hard to tell from the photos.
it may be that your feed rollers are "slipping" on the stock causing it to streak.
Can you print & show pictures of of each of the following on 20# white Tabloid (11x17)?
1. 30% Cyan flood
2. 30% Magenta flood
3. 30% Black flood
4. 30% yellow & 5% cyan flood (you need the cyan so you can see the yellow)

guessing on the sheet size and estimating the spacing, it looks like a drum problem. did you try a SECOND new drum? I have had brand new drums DOA from Xerox.

--> I'm assuming you do not have a service contract? My tech will be in to fix a broken drawer for me tomorrow, I'll see if he has any ideas...

 

[veronika_zoobs]

If you measure the distance between streaks (or between good, solid areas) and it turns out to be more or less uniform then it could be a roller that needs to be cleaned.
In the case of a dirty or worn roller, the distance between the marks will indicate which roller needs to be looked at. Because we've got a service contract I have no experience servicing this part of the machine myself so I couldn't tell you how to determine which roller it is.

our technicians have been replacing the Magenta developer housing, based on their service notes its been replaced 4 times this year already. Yesterday he replaced the Cyan developer housing as well, we have a service contract with Xerox.

You should try some test patterns in other colors to see if this is a cyan issue or not.
Might try swapping a fuser, and have you changed the corotron? You said new developer but have you changed the housing? I'd say either a corotron or bad cyan housing.

EDIT: Of course now I'm confused which way these are running through the printer, I think what I thought was the process direction is not.

These are running through the printer SEF.
Our technician changed the Cyan housing yesterday as mentioned above, but we will try the corotron now!
Other "pastel" colors rendered the same results, light magenta light cyan, etc, with just a crappy quality over the whole area.

is your text or solid line blurred in any way? It's hard to tell from the photos.
it may be that your feed rollers are "slipping" on the stock causing it to streak.
Can you print & show pictures of of each of the following on 20# white Tabloid (11x17)?
1. 30% Cyan flood
2. 30% Magenta flood
3. 30% Black flood
4. 30% yellow & 5% cyan flood (you need the cyan so you can see the yellow)

guessing on the sheet size and estimating the spacing, it looks like a drum problem. did you try a SECOND new drum? I have had brand new drums DOA from Xerox.

--> I'm assuming you do not have a service contract? My tech will be in to fix a broken drawer for me tomorrow, I'll see if he has any ideas...

Our text nor the line are blurred, they are clear. I don't think it's the feed rollers because as you mentioned, the text or lines would be affected.
We also get DOA parts from Xerox, and the drums are replaced as needed, sometimes more often than others because of the crappy refurb job they do, or we replace one and it doesn't work.
Looking forward to hearing if your tech has any tips, the one that came in for ours isn't our usual tech but he confirmed what has been replaced.
I'll run those sheets you requested soon!

 

[Alith7]

Our text nor the line are blurred, they are clear. I don't think it's the feed rollers because as you mentioned, the text or lines would be affected.
We also get DOA parts from Xerox, and the drums are replaced as needed, sometimes more often than others because of the crappy refurb job they do, or we replace one and it doesn't work.
Looking forward to hearing if your tech has any tips, the one that came in for ours isn't our usual tech but he confirmed what has been replaced.
I'll run those sheets you requested soon!

I'm sorry, I was dealing with a customer when my tech came in and he was in and gone before I could ask him!
if you can run those test sheets, and also, do you have the check sheets to put against your test prints to help narrow what part is causing the problem?

 

[Alith7]

Also, have you replaced the fuser?

 

[veronika_zoobs]

do you have the check sheets to put against your test prints to help narrow what part is causing the problem?

You mean the sheet that I had posted initially?

Also, have you replaced the fuser?

The Fuser is new, but we are going to replace that and the Corotron too. We printed the same art on a Xerox 770 (Manager's brother has that at his facility) and had the same results as I originally posted.

 

[Alith7]

See attached.

 

[mojoprime]

as far as i know, and from discussions with our techs, this is the banding problem that's been affecting this machine pretty much since it came. we've had ours for four years and some change, and have pretty much had that issue since the beginning. tech supports told us it was an issue but offered no solution. the techs just threw up their hands because they could literally change everything out and still have the issue.

turns out, when one of our techs came recently on something else, that the engineers have determined it to be a hardware issue -- i believe -- in the developer housings. they're replacing them as the old ones fail -- which sucks, because the machine itself has been discontinued -- but you might ask your xerox tech about them. it's a really frustrating issue, but know you're not alone. some have managed to correct the banding by taking the affected area into photoshop and adding a little noise to it. i never got really positive results doing that but YMMV.

 

[Alith7]

as far as i know, and from discussions with our techs, this is the banding problem that's been affecting this machine pretty much since it came. we've had ours for four years and some change, and have pretty much had that issue since the beginning. tech supports told us it was an issue but offered no solution. the techs just threw up their hands because they could literally change everything out and still have the issue.

turns out, when one of our techs came recently on something else, that the engineers have determined it to be a hardware issue -- i believe -- in the developer housings. they're replacing them as the old ones fail -- which sucks, because the machine itself has been discontinued -- but you might ask your xerox tech about them. it's a really frustrating issue, but know you're not alone. some have managed to correct the banding by taking the affected area into photoshop and adding a little noise to it. i never got really positive results doing that but YMMV.

huh. Didn't know they were(did apparently) discontinuing it. My 700i was brand new in December. Given the number of them that are out there and that they were still selling them on 3-year lease contracts only a little over 6-months ago, I would assume that it will be a long while before they stop servicing them. Now I know why were able to get the killer LOW click rates we got...LOL.

That said, the Devloper Housing makes sense. Have you techs tried to replace those?

EDIT---> I see they did, on the magenta. I would look at the fuser, then maybe the developer housings.

 

[GuruMorgor]

Are you able to adjust the transfer voltage? On our Canon, when setting up paper profiles there is an option which allows you to increase/decrease the transfer voltage. Raising it will pull more toner to the sheet. Also see if there are options like (toner reduction) and (image smoothing) turn them off, might help.

 

[mojoprime]

guru, i haven't tried that. ultimately, i gave up and tried to print as much white as possible.

but the techs said it was the developer housing, something about a gap that was large enough that it was creating the issue. enough that they were replacing the housing as they got the parts in -- there was a patented "xerox shortage" on the parts. much like the toner issue some time back.

the thing that ticks me off is that they waited until the machine was discontinued to figure out the issue. i understand these things take time, but you can't tell me that in all of the beta testing and pilot testing, that no one ever saw banding in the gradients and solids over a variety of substrates.

guess that's why it might be EOL'd.

 

[TekniKal]

All digital print systems will exhibit banding or pitch marks in light halftones to some extent. This is caused by mechanical noise being shown in the halftone pattern. This is why you can't use the same full coverage backgrounds that you would normally use on a press. Pick your colors carefully, try to use primary colors or patterns instead of solids. Another fix is to use a line screen instead of a dot screen. White space is your friend....

 

[EZPower]

My understanding is pastel colors for solid backgrounds don't print well on digital machines. It's a limitation. We are aware of it. We show a client a proof, and let them decide to go digital or press. CMYK or PMS. Some clients want quality and are wiling to pay for it.

 

[rsands]

Digital and there is not much to solve it unfortunately. Since we went KM it has shown good improvement compared to the 700

 

[Alith7]

and I'm seeing the opposite. my 700 is a HUGE improvement over my C6500. and my uptime is almost 100%. compared to our copy centers which have live-in techs for their KMs. Pastels are no problem either. the only two issues I've had with it in 10 months is that the drawers are SUPER crabby about auto reading paper size, and it's not great on textured stocks like linen. that was one thing the KM machines did well.

 

[rsands]

haha thats strange because the textured stocks we used worked wonders on the linen on 700 but terrible on C8000. Goes to show each unit really does have its own performance ups and downs

 

[xeropros]

Banding 700

Banding 700

as far as i know, and from discussions with our techs, this is the banding problem that's been affecting this machine pretty much since it came. we've had ours for four years and some change, and have pretty much had that issue since the beginning. tech supports told us it was an issue but offered no solution. the techs just threw up their hands because they could literally change everything out and still have the issue.

turns out, when one of our techs came recently on something else, that the engineers have determined it to be a hardware issue -- i believe -- in the developer housings. they're replacing them as the old ones fail -- which sucks, because the machine itself has been discontinued -- but you might ask your xerox tech about them. it's a really frustrating issue, but know you're not alone. some have managed to correct the banding by taking the affected area into photoshop and adding a little noise to it. i never got really positive results doing that but YMMV.

I have the solution call me 619-917-2647

 

[MailGuru]

Did you replace the Fanatney Rod?