Cyan Overspray on Blue Prints (CET UV Hybrid)

[tylercrum]

We have a CET hybrid uv printer, with ricoh gen5 heads, 2 print heads (Black/Cyan and Magenta/Yellow). We recently had a new head installed for black/cyan and we are having a problem with the cyan. I'm attaching a picture. We have the "static bar" setup installed, we clean the materials with an anti-static spray, and we have the humidity in the 40-50% range (usually closer to 50% but occasionally it dips down to 40 or so). The problem is the cyan overspraying, but it only does it on prints that are mostly blue. I can print a photograph or some other full color art and it prints just fine, but then a job that's mostly blue prints with this overspray. The other day we actually had two 24x18 coro boards loaded, both with different art and printed them side-by-side and the one with mostly blue text had the overspray but the other board did not. I can get the problem to go away for a short time if we shut the whole printer down and let it sit for a bit. (which makes me think it's NOT a faulty head, but more of an electrical issue) But it comes back, and it seems to be coming back sooner and sooner, to the point that I have to shut the whole printer down a couple times a day, which obviously isn't going to work in the long run.
I have zero problem getting my hands dirty and fixing things myself, but I'm out of ideas on this one, other than throwing money and random parts at it.
(For the record, we ruled out it being some sort of a rip issue, by pulling a few old jobs from the archives that printed fine before the new head install and they now print with the overspray if they're blue.)
Any thoughts would be appreciated.

 

[tylercrum]

Also, forgot to mention that it does not discriminate between substrates. It does it on poster paper, coro, styrene, foam board, aluminum, magnet, banner, etc.

 

[Solventinkjet]

I don't know that machine at all but it uses the same heads and technology as the JFX200 which I do have experience with. There should be an air pressure adjustment you can do. I would start there and make sure it isn't too high or too low.

Edit: Never mind those don't use gen 5 heads.

 

[Terry01]

Getting a deflection in your test prints??? The heads on those printers are the ricoh GH2220 series.
Swap your printheads over as they will be very close without a recalibration an see if it changes to the
magenta and yellow head. Probably just needs a good flush

 

[flyplainsdrifta]

as far as i know, you would not see static on things like foam and poster paper. i would look closely at the head to see if there is some sort of deflection going on.

 

[ChrisN]

Yeah, what do your test prints look like? What does the head alignment print look like? I'm curious if the head fires in a straight line.

I don't think it's negative pressure related. If the pressure was too low, you would get ink dripping from the heads, but I doubt you would get individual deflected droplets like this.

 

[Ahmed Samy Nagada]

I'm not familiar with this machine, but I had similar problems with Cyan using KM and DX7 printheads, the KM problem was solved by adjusting voltage, DX7 was a defective printhead.

 

[Grizzly]

This could be a voltage issue. Most likely that it is too high. This could also be an ink temperature setting. I have an AGFA Titan HS that has Ricoh Gen 5 heads and when I changed white ink, it would have overspray like this because the previous ink needed a higher temperature for the right viscosity. Once lowered, the problem went away. If it the ink viscosity is really low, it can cause overspray like this.

 

[tylercrum]

This could be a voltage issue. Most likely that it is too high. This could also be an ink temperature setting. I have an AGFA Titan HS that has Ricoh Gen 5 heads and when I changed white ink, it would have overspray like this because the previous ink needed a higher temperature for the right viscosity. Once lowered, the problem went away. If it the ink viscosity is really low, it can cause overspray like this.

Grizzly, you're awesome. I don't care what these other guys say about you. ha Kidding.
But seriously, I adjusted the temperature down a bit and it seems to have cleared up. I ran a few test prints and so far so good. Hopefully that fixed it.
thanks again everyone!

 

[Grizzly]

Grizzly, you're awesome. I don't care what these other guys say about you. ha Kidding.
But seriously, I adjusted the temperature down a bit and it seems to have cleared up. I ran a few test prints and so far so good. Hopefully that fixed it.
thanks again everyone!

What has everyone been saying about me? I guess I missed it. Whoosh!
Glad that cleared it up!

 

[justntym]

This could be a voltage issue. Most likely that it is too high. This could also be an ink temperature setting. I have an AGFA Titan HS that has Ricoh Gen 5 heads and when I changed white ink, it would have overspray like this because the previous ink needed a higher temperature for the right viscosity. Once lowered, the problem went away. If it the ink viscosity is really low, it can cause overspray like this.

I run a Mimaki UCJV300-160 using the Ricoh Gen 5 head and your diagnosis was spot on. After doing a #Adjust: #Head Voltage test print and adjustment, my cyan overspray issue was resolved. I had a full wall wrap printed except for 1 panel when the color shifted. Been trying for a week to fix the issue and this adjustment did the trick. This wall wrap was a dark turquoise color and when the overspray issue started on the last panel, the colors didn't mix right causing the shift. It's now back to the correct color which saved me $1500 in material cost and a lot of time reprinting. Also saved me from putting in a new head which was the recommendation given to me, so there's another $2700 saved.

 

[Grizzly]

Glad I could help! And saved you money. Win Win!