CET Varnish Experiences?

[MDKAOD]

Hey all, we're taking delivery of our new CMYKWx2 500Q on Monday and we've been kicking around adding varnish to the line up. We're upgrading from a Roland LEJ640 which has the varnish and have a couple of clients who use it intermittently. I'd hate to lose the capability, but my rep is strongly recommending against a varnish set up on the CET. He keeps telling me it's a "headache dipped in a pain-in-the-***" if we're not running it daily.

It's my understanding that on the CET the varnish is a chemical process more than a UV cure process, therefore the lack of a capping station leads to the solvent drying up on the head. I'm looking for real world experiences of anyone running a CET with varnish. Can we just keep the line flushed when we don't have varnish work?

Any and all experiences welcome.

 

[synergy_jim]

varnish on a hot cure UV system is pointless. You can't get the effects you get with a LED cure system. Its way cheaper and less hassle to laminate or spray clear on a print than messing with a varnish system.

 

[chrisphilipps]

My experience is with the Flora, not the CET. The varnish in the Flora doesn't have any real issues with drying up. The main issue with it is it's a dust magnet. If you are in a dirty environment or if you are by an air conditioner/heater vent you will get particles in the varnish and it will not be smooth to the touch. I have also found that printing varnish is a three step process. You print your image first, print the varnish really heavy with no UV lights on and finally send the carriage back over and just run the UV lights to dry the varnish. I currently only have one install that I was involved with that still has varnish in their printer, the other 6 installs just have CMYKW.

 

[MDKAOD]

varnish on a hot cure UV system is pointless. You can't get the effects you get with a LED cure system. Its way cheaper and less hassle to laminate or spray clear on a print than messing with a varnish system.

Good point, I should clarify I'm not intending to use the varnish as a replacement for laminate. I'm interested in special effects and texturing.

My experience is with the Flora, not the CET. The varnish in the Flora doesn't have any real issues with drying up. The main issue with it is it's a dust magnet. If you are in a dirty environment or if you are by an air conditioner/heater vent you will get particles in the varnish and it will not be smooth to the touch. I have also found that printing varnish is a three step process. You print your image first, print the varnish really heavy with no UV lights on and finally send the carriage back over and just run the UV lights to dry the varnish. I currently only have one install that I was involved with that still has varnish in their printer, the other 6 installs just have CMYKW.

Good insight. I know the Flora and the CET units are similar, correct?

 

[artbot]

had varnish on a cet fk. was so excited about it. total waste of time. i'm not sure running it daily would even do the trick. you'd thing "varnish has no pigments so it will clog the least". it clogs more than white. constant drop out. or maybe i'd call it blow out due to the fact that it couldn't print long distance.

 

[MDKAOD]

had varnish on a cet fk. was so excited about it. total waste of time. i'm not sure running it daily would even do the trick. you'd thing "varnish has no pigments so it will clog the least". it clogs more than white. constant drop out. or maybe i'd call it blow out due to the fact that it couldn't print long distance.

I was hoping you would stop by, short of PMing you, as I figured you played with varnish at some point with your unit. I actually want to thank you since reading many of your posts regarding your experiences with CET weighed heavily on our decision to purchase.

Are you running the Kyocera or the Gen4 Ricoh heads? Would it matter in your opinion or is this an ink problem? Is the varnish a situation where you can flush the channel and prime it when needed?

 

[artbot]

right now using a rastek with toshiba ca4 heads.

could be so many things that would cause the issue. was interesting to see at the top of the thread that they are chemically different. one would think that it's just the resin without pigment. the varnish did dry out or cure clogging nozzles.

whatever you do to keep it flowing with purges, and running solvent in that channel and such that still doesn't get tot he main problem. it's called "varnish" but it's not shiny. cured in pass with printing, it has a semigloss grain to it. post cured (lamps curing on the way back) it is shinier but can orange peel a bit. i've seen the roland varnish and it is clean and really pops. not what i got out of the cet varnish.

 

[MDKAOD]

right now using a rastek with toshiba ca4 heads.

could be so many things that would cause the issue. was interesting to see at the top of the thread that they are chemically different. one would think that it's just the resin without pigment. the varnish did dry out or cure clogging nozzles.

whatever you do to keep it flowing with purges, and running solvent in that channel and such that still doesn't get tot he main problem. it's called "varnish" but it's not shiny. cured in pass with printing, it has a semigloss grain to it. post cured (lamps curing on the way back) it is shinier but can orange peel a bit. i've seen the roland varnish and it is clean and really pops. not what i got out of the cet varnish.

That's what I wanted to know. Thanks for the insight.

 

[5Star]

My experience is with an Arizona 460GT (and a JF1631 before it), but may be some help to you.
I've taken the varnish out of the machine & am running CMYKWW now.

Although the flatbed work area looks very clean, it is contaminated by airborne paper dust from our large offset area.
You'd swear that there's no dust issue here, but look in the spots where the cleaner doesn't get to, and there's a thin, pale grey film of dust everywhere.

The issue is that if I try printing varnish, the airborne particles are attracted to the printhead area like they're magnetic (static charge, actually). Even wiping just before the printhead arrives doesn't help. The microscopic particles cause pin holes in the varnish, making the job look decidedly cruddy. Even 5c sized spot areas end up with a pin hole or two.

For the few times we were requested clear on a job, we tip nearly all of it down the drain with daily head cleans, and still end up with a below par job.

A pressurised clean room would fix the issue, but the Return On Investment numbers don't really stack up.

As far as drying out and clogging, I find both the white and the clear will clog more readily than the CMY or K.

Maybe some of this can be applied to your situation. Maybe your rep has had similar experience and that's why he's not too keen on the idea.

 

[MDKAOD]

I'm not interested in flood coating. I'm strictly interested in textures and embossing with the varnish, however, it seems that Roland was able to overcome this because of the capping station on the LEJ640 and the enclosed environment. Roland basically did exactly what you suggested with a pressurized enclosed print chamber.

It's sounding like this is something that no flatbed manufacturer has been able to overcome.

 

[MrNick86]

Just my insight, though I have zero experience with printing varnish, I would think a higher head temperature would help lay the ink down thinner and allow for more of a gloss. Am I wrong?

 

[artbot]

the wetting out is more of a time/temp oriented thing. just like when spraying a clear, the material hits the substrate then dot gains to a mass then builds/settles and develops a meniscus. so a cool clear will wet out a bit less thus building higher to create a taller rounder meniscus. that's my theory.

 

[MDKAOD]

I can relay my experiences with the Roland to maybe shed some light on how embossing is achieved. For matte, the Roland varnish passes both UV LED's over the varnish pass, and for gloss, it only powers up the left LED lamp. My theory was always that the extra heat from the second lamp is causing the varnish to bubble slightly to give it a more matted finish. When I say matte, Roland's matte is actually the same finish as the other inks and is more of a satin finish. The gloss is a very nice pop/polish.

To achieve the embossing effects, the Roland will pass however many layers of matte required then finish with a glossy top layer which gives a nice domed effect.

I really should post a picture of some of the texturing projects I've been working on lately. Maybe once our CET is settled in, I'll get some good shots of the textures for you guys.