Banding problem

[Colin]

*I posted this in the Roland section yesterday, but no reply, so trying here.

Roland SP-540i

Whenever I print a solid color background, I get these lighter colored bands about every 17", but the distance varies. Printing at Standard Quality in RVW. I've even tried converting the colored area to a bitmap (in CorelDraw), but that doesn't fix it. All test-prints are good, and all is clean; new wipers.

Any solutions?

 

[DerbyCitySignGuy]

Vertical or horizontal lines?

Assuming horizontal lines, since it looks like an ink starvation issue. Probably only happens when you print large blocks of the same color?

 

[Colin]

Probably only happens when you print large blocks of the same color?

Yes. The lines are along the path of the print head.

 

[Colin]

So what would cause an ink starvation if all of the cartridges have plenty of ink? And why wouldn't that starvation continue, rather than being a brief band?

 

[DerbyCitySignGuy]

So what would cause an ink starvation if all of the cartridges have plenty of ink? And why wouldn't that starvation continue, rather than being a brief band?

The cartridges don't feed ink directly to the heads, so it could be anywhere between your ink cartridge and your print head. I'd start by checking for a clogged damper.

 

[Solventinkjet]

So what would cause an ink starvation if all of the cartridges have plenty of ink? And why wouldn't that starvation continue, rather than being a brief band?

Ink starvation almost always means there is air getting into the system and that usually happens at the damper area. The damper also has a filter that can clog and cause starvation. The reason it doesn't just continue to drop out is because the starvation is not enough to completely drop that head but just enough to cause issues once in a while. I would replace the dampers and the o-rings and that should fix the issue. If it doesn't then you might have a feed motor issue or even a head problem.

 

[Colin]

Thanks Vander and Derby. The dampers were replaced not too long ago, but perhaps they could still be the culprit? The machine is 8 years old (but gently used), so could those little tubes plug up?

 

[Gino]

It could also be your signal is dropping out, ever so slightly.

 

[DerbyCitySignGuy]

Thanks Vander and Derby. The dampers were replaced not too long ago, but perhaps they could still be the culprit? The machine is 8 years old (but gently used), so could those little tubes plug up?

Possibly. Usually the dampers are the first thing to check, since they're cheap and easy to replace. If they're clogged again, you might need to investigate why they're clogging so much. If you're running it 24/7 you might just have to replace them more frequently. Running third party ink?

Like Vander said, replace the o-rings and dampers and if you're still having the issue you most likely have air getting in somewhere else. There aren't really too many places air can be introduced along the way and even if air does get in, the dampers are there to get rid of it. I'd wager dollars to donuts that replacing dampers and o-rings will fix the issue.

 

[signgal605]

I've had similar problems. We found it was from uneven heating. You might try playing with the heat settings.

 

[papabud]

i would look at the heater.
one other area could be the material itself.
i had a few rolls that wasnt stored properly and they had a "dead" spot.
and ink never laid down right along that line and it repeated. look at the material before its printed. if you see a line in it then that could be the problem. the line will be very faint. kind of like the sheen is a little different.

 

[Colin]

Possibly. Usually the dampers are the first thing to check, since they're cheap and easy to replace. If they're clogged again, you might need to investigate why they're clogging so much. If you're running it 24/7 you might just have to replace them more frequently. Running third party ink?.

Yes, 3rd party ink. Rite-Media ProColour, from All Graphic Supplies.

 

[Colin]

I would look at the heater.

I thought of that; I had the heater at 44, and turned it down to 40, no difference.

There's one possible correlation that I observed when printing, so (anyone) tell me if this makes sense:

When I intermittently spooled off some material from the 54" roll of vinyl during printing, that moment of spooling seemed to correlate to the lighter line appearing, but I can't think of why. Static?

 

[DerbyCitySignGuy]

Yes, 3rd party ink. Rite-Media ProColour, from All Graphic Supplies.

Shouldn't make a difference, but I do know that some people have issues with third party inks. Recent switch or have you been using that brand for a while?

I also highly doubt that hand spooling some material would make a line like that. That's an almost textbook starvation symptom.

 

[Colin]

Have used this ink for some time, not recent.

 

[DerbyCitySignGuy]

Have used this ink for some time, not recent.

If you've had no issues to date with that ink, I think you're just gonna have to bite the bullet and replace those dampers again. At least it's relatively easy!

 

[Colin]

If you've had no issues to date with that ink, I think you're just gonna have to bite the bullet and replace those dampers again. At least it's relatively easy!

Yes, thanks for the help.

The only other thing I can think of is that the lines in the print appeared every time the power went out, and then came on again.

(Just kidding)

 

[Colin]

Local rep/tech is suggesting a flaw in the media (Arlon - matte cal), so I pulled about 4' through the front of the printer, and didn't see any apparent lines, but given that it's matte, it's tough to be sure.

 

[Colin]

OK, I know some of you love to build on your knowledge of all things printing, so here’s one to chew on:

My rep/tech suggested that I try a different profile, and while I was skeptical that that’s where the problem lies, I tried it (Generic Vinyl 1) and while it was printing, I spooled off material from the roll at the back of the machine, and then immediately made a little mark with a Stabilo pencil on the edge of the roll right where it was printing, and sure enough that is exactly where a lighter line in the print was born! This confirms my prior suspicion about this possible correlation.

When I clasped the media flange to turn the roll, I could feel static electricity with my hand. So doesn’t this strongly suggest that static is the issue?


http://support.rolanddga.com/docs/d...es/static suppression for roland printers.pdf

 

[RPM]

All are great answers and possibilities. Have you also done a PF adjust anytime lately? Just throwing out one other possibility that you may have a little contamination on
encoder. Probably unlikely but just one more thing to rule out.....