Things they don't tell you about UV flatbed printers

[ElJay]

Any minor flaw in the media (scuffs, scratches, streaks, etc.) will appear in the finished print, even with heavy coverage. This is especially true with styrene. The sheet will look spotless before printing, but scuffs and scratches will magically appear.

Even with more than adequate curing time, the ink still scratches and shows fingerprints easily.

Regardless of what they say, there are some things the ink just WILL NOT stick to, especially the white. Clear acrylic and brushed aluminium immediately come to mind.

They are some of the most tempermental machines I've ever worked with. Anything coming within the slightest contact with the heads results in banding and ink drops.

They'll print screaming fast...as long as you don't care what the finished product looks like.

It's been a rough week....just had to vent a little bit. Anyone else?

 

[omgsideburns]

What printer are you talking about?

 

[Gino]

It only stands to reason...... if you are putting down a really really thin coating of transparent ink onto a substrate that has flaws in/on it.... these flaws will still show through the thin ink coverage. As for printing over grease spots from fingers, it is told to you by the manufacturer, these things must be cleaned before printing.

Many places are now asking if something is for flatbed printing and if so...... they will handle with gloves, but that's not to say some of this sh!t from China hasn't already been contaminated. For that matter, from anywhere it could be tainted along it's route to you.

Do you use gloves when piling it on the printer ??

 

[Banners Signs Etc.]

I have Gandi 1224 it covers grease, scratches whatever...I guess I should feel lucky....Use more ink lol

 

[iprint]

Buy quality substrates and you can produce quality signage. I try to always purchase in case quantities/pallet quantities. Less handling = less chance of contamination.

 

[ElJay]

I suppose I was a bit cryptic in my OP...

It's an Oce Arizona 360TX (or Fuji Acuity..same printer). I've been running it hard for about two years and these are just a few of the general issues I've encountered.

The scuff/scratch issue is almost exclusively with styrene. I clean it throughly with a 50/50 water/denatured alcohol mix. Styrene is cheap, so I think a lot of the time it gets treated rough before I recieve it. But as I said, it will look totally clean until I print on it...But I guess that's not the printer's fault.

The scratch/fingerprint issue with finished prints is a big one. I have my lamps set appropriately (hot enough to cure the ink, but not hot enough to curl or buckle the media)....and I understand that even after that they still need a day or two to outgas (not that we ever get that, we print and ship same day more often than not). It just seems like durability is a big problem.

Yeah..White ink is a problem on clear acrylic. You can use adhesion promoter, but it's nasty stuff to work with and it's expensive.

For my particular machine, I'd say it requires more cleaning, maintenance and babying than others.

The express mode doesn't produce an acceptable level of quality for our purposes.

This is probably what I should've posted to begin with. I guess it's my roundabout way of asking if anyone else had any of the above problems and how they can be resolved/avoided. My apologies if I've confused anyone.

 

[Banners Signs Etc.]

outgas?? Is the vacuum table not sucking enough to be able to nuke the substrates without buckling?

 

[ElJay]

Outgas probably isn't the right word. Cure is probably a better one. The vacuum is holding down the media just fine, but if I crank the lamps up too high it will cook things like styrene, PVC and MDF.

 

[Banners Signs Etc.]

especially if you're not printing full width....used to work on an old colorspan sometimes we would have to sit the prints out in the sun for a few hours lol

 

[Ponto]

Cleanliness is supreme as you've likely encountered...and perhaps the bulbs need replacement if curing has become an issue. You should have access to a table which recommends the bulb intensity for various substrates and if you need to jack up those values for proper curing the bulbs are likely showing their age.... IMHO and experience with the Acuity.

JP

 

[darrell]

I printed on styrene for several years and buying 400 sheets was the norm mostly 0.040.
We had a quality issue where a manufacturing line showed after printing (0.060).
So I ran the sheets through our corona treater and it eliminated it and the printing turned out beautiful. Corona treated styrene has a shelf life. We also wore cotton gloves when handling. With good quality materials that are handle properly the problems can be overcome. Aside for Sintra I used water only then buffed with a dry cloth and dusted with a California car duster, avoided alcohol cleaning except for grease marks and oily fingerprints.

 

[darrell]

UV inks are sensitive to a certain wave length of UV light. And different brand inks are sensitive to different wave lengths. As the bulbs age they don't produce as much UV and when there turned up the IR (infra red) radiation is also increased producing more heat. There are meters that will measure UV lamp output, but most operators run them until curing just doesn't work

 

[SecondCityPrint]

We have an OCE 350gt... same problems... for cleaning we use a mix of 1/3 isopropyl, 1/3 water and 1/3 simple green (helps to degrease). Spray the stuff on, get a swiffer covered with clean cotton rags, wipe it smooth and THEN with another clean cotton rag, buff out the remaining mixture till totally dry. Won't hide physical scuffs but gets rid of any dirt or grease and has generally worked well for coro, sintra, gatorboard and styrene.

 

[DoubleDown]

I'll give you some help.

First, do you have access to the OCE support area and all the whitepapers?

https://dgs.oce.com/

Go to Printer Support - Customer Access

Pick your corresponding printer in the Arizona realm.

Find the application bulletins and go nuts with all the info you could ever need.

Then find this one, if you follow this to a tee and the other guidelines you will have no issues. You MUST keep the undercarriage clean everyday, you must keep dust and static around the machine to min and yes you must use a primer OR lightly sand the clear acrylic before printing UNLESS you buy digital acrylic and you won't have to worry about it. Don't complain about the price of the promoter if you are wasting prints, doesn't make sense. The promoter lasts a very long time.

Media Notes, Revision C - Recommendations for Printing on Various Media Revised March 22, 2010

We print a TON in express mode perfectly and it looks amazing. Lamps are key, cleaning is key, and cleaning the reflectors every time you change a bulb is a HUGE key.

Read, read, read all these documents and you will learn a ton.

Always wear cotton gloves period.

Scratches mean bad ink adhesion which means bad lamp power either too much or too little. We run our pvc on 5 for example with NO scratches ever.

 

[DoubleDown]

oh yeah and watch the printhead maintenance video.

 

[FireSprint.com]

Buy quality substrates and you can produce quality signage. I try to always purchase in case quantities/pallet quantities. Less handling = less chance of contamination.

+1

I hate buying product that isn't sealed in a skid if I can avoid it.

 

[MikeD]

I just looked at the Oce Arizona 318 GL yesterday and was impressed...now I'm a little hesitant after reading this post. The demo was on Falconboard and the results looked good in Quality mode. However, my intention would be 2nd surface on clear acrylic. From what I read above, it's not as easy as printing on the demo material.

What has your experience been with clear acrylic? Does the acrylic need pretreatment?
If the UV ink is going to be 2nd surface, and the final piece will have a backer on it for protection, does that make the process a little easier (less labor intensive) and the product more durable?

Thanks for your insight!

 

[DoubleDown]

great machine but like ANY other machine you have to take care of it and do your homework.

2nd acrylic is not a problem but you do have to prime the material or use the digital print acrylic. We just did 100 sheets 2nd surface and they turned out perfect. Key is to keep your heads clean.

 

[WinGraphics]

I'm in the market for a used machine. I screwed up 4 years ago when i bought a Colorspan 5465 and i want to trade up to a solid, quality used machine of which i have found several. The Colorspan was a first generation machine with lots of problems. I know that Oce 350GT is a good machine, however, the one i am looking at is the Oce 250GT. The 250 is the first one in the GT line and I was wondering if that one was a problem child or a solid machine? One mistake was enough for me and i really cant afford to make another. Any feedback is appreciated.

I am also curious about the 2 ink sets that Oce has. One has better adhesion but slightly lower print quality. Does anyone have experience with that in the older machines? Some people have commented about their Oce's being finicky when printing on some materiels. Which inkset are you guys using?

Thanks for the help!

 

[DoubleDown]

Oce is a good machine, really is. People don't really get rid of them because they print so nice but the older machines are slower. How old is the machine?

We use the harder ink set, better trust me.

 

[nuke]

Also looking

Not to hijack the thread but There seems to be big differences in the inks as well as the machines, which inks and or machines work best for acrylic and coroplast.
Thanks for the thread cause I need all the help I can get.