Eco-Sol Printing: Solid Colours - Tips/Advice

[Custom_Grafx]

Ok... so I'm doing a really long run of solid darks... and I'm officially going insane.

I'm getting there, and have found a couple of things which have helped. Just wondering if there are any other tips out there to help people down the track.

I've searched and read quite a bit, but was hard to find one good thread that dealt with problems specifically related to printing large areas of solid colour.

Threads I found useful were about ink starvation, banding etc etc.

Basically I've been getting what looks like ink starvation... but am being told it's most likely a feed issue. A tech will be coming out within the next week so I will keep this thread updated with news.

Thus far, my fix has been to play with the feed calibration settings - which to be honest, aren't really convincing me at this point. Test print says one thing, reality says another.

Reducing head speed has helped, but it wasn't the only thing.

I have found heat to be another possible culprit. Even though the weather has started to cool down in Sydney, I'm getting better results with lower heat settings... Anyone got an explanation for that?

Also, using a profile which has slightly higher ink limits, is proving to be contributing to what seems like a bandaid fix at the moment.

 

[seesaw signs]

mate what printer are you using? what rip software/profiles?

we have issues here with solid colours banding (a broad 20-30mm strip with colour drop out) intermittently. Humidity does have an effect, as do the heater settings and profile used. I tried fiddling with the feed speed but it didn't really help.
bottom line is that i tend to print solid colours out of flexisign/production manager not versaworks, and if i want it to be really solid i'll select a 2x overpass in production manager - but that takes alot longer to print.
it's a real head f~^(!, I know what you mean about it driving you nutty.
good luck,
neil.

 

[Bly]

Sometimes you need to increase the number of passes instead of/as well as slowing down the head speed.

Printer, RIP, settings?

 

[Custom_Grafx]

Thanks guys,

Printer: VS640 dual CMYK
RIP: VersaWorks
Settings: Had same effect/problem apparent on an 8 pass and a 12 pass profile.
Head speed: Happened on 760mm/sec and on 500mm/sec.

These two profiles I had made myself. I then tried a manufacturer profile which had a higher total ink limit - and it was much less problematic. I'm only making an educated guess here, in thinking that more ink equals more chance of the ink bleeding into each other making it harder to see the imperfections in feed or other settings? Is this true?

Maybe I should set my profiles based on higher total ink limits to mask these problems?

I'll post a couple of pics too.

 

[Custom_Grafx]

Here's a couple of samples...

 

[GAC05]

What media are you printing on?
Have you been able to get good results on similar jobs with it before?
I don't have a Roland but have hit this before with my vj1304.
Seems that some materials just would not print good solid blocks of dark color.
Others are almost flawless even using a lower quality(faster) setting.

wayne k
guam usa

 

[Custom_Grafx]

Yes it's somewhat a phantom issue... but I want to find that phantom when it's 4.5 metres and 90ml ink that goes down the drain when it appears 3.5m into the print.

In the samples posted, the blue is a gloss clear, and the other is matte polyprop... so material doesn't matter.

It's not a consistent pattern either... the only consistent thing about it, is that it's random and intermittent.

I have also wondered about the number of pinch rollers... I use 2, even on 1524mm media, I tried using 4, but I could see a mark on the solid when doing that so went back to 2 again...

 

[Bly]

I've struck this before too. I think increasing the number of passes was the answer.

 

[Custom_Grafx]

I've struck this before too. I think increasing the number of passes was the answer.

The next step up is 16 pass... was trying to avoid that as much as possible coz it takes so long... but if that's what needs to be done... I guess it's better than pulling your hair out eh?

 

[Custom_Grafx]

Ok, so the tech just came and left. He found that the capping station wasn't straight so it wasn't sealing properly, causing ink starvation.

He straightened it and gave it the all clear... now I just have to try printing some dark solids again.

Hope this has fixed the problem.

 

[Rooster]

Less heat allows for a little more ink bleed, same thing with higher ink limits.

Usually ink starvation is usually related to the dampers. Since the capping station has no bearing on the delivery of the ink once printing, it's unlikely to have solved the problem.

Switching from bi-directional to uni-directional is usually a quick and dirty way to see if your experiencing ink-starvation. Epson piezo heads are notorious for it at faster speeds and especially with darker deeply saturated colors. A higher number of passes will also lay down less ink per pass (in addition to smoother screening) so it's also a good option to check for starvation.

Also make sure your machine is sitting perfectly level. The ink is gravity fed for the most part, so if you're forcing it to flow up hill it will naturally cause a restriction in flow.

 

[Custom_Grafx]

Thanks Rooster, will be doing some similar job today and post back re results.

 

[Custom_Grafx]

Ok, I'm doing the reprint now... and on 8 pass, I am more than 1 metres into this print, and so far, it is flawless (touch wood).

Further precaution taken, I slowed down the feed rate from the canned 16mm/sec to 8mm/sec. Head speed is at 700mm/sec. Heaters are at 40/42.

I also did a bi-directional calibration, which was actualy 1.5 points off, and a feed calibration just in case as well.

Fingers crossed.