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Latex Profile Issue

jasonx

New Member
Hey guys,

What would you say is the problem with this profile? This occurs randomly throughout the print in different colours and obviously more noticeable in solid areas.

Ink limits, heat, airflow?

Any ideas appreciated.
 

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ddarlak

Go Bills!
i can't really see the issue, but i'd have to say there are two answers to this, material contamination or air quality (humidity)
 

dypinc

New Member
Ink coalescing, media issues no doubt if randomly occurring.

A couple things you can try. More passes, up drying heat, up airflow. Relinearizing keep light inks to a minimum and nothing beyond 50%, lower ink limits and create new profile.

What is room temp and humidity?
 

jasonx

New Member
Ink coalescing, media issues no doubt if randomly occurring.

A couple things you can try. More passes, up drying heat, up airflow. Relinearizing keep light inks to a minimum and nothing beyond 50%, lower ink limits and create new profile.

What is room temp and humidity?

This is at 16p. Upping it from 10 to 16 has helped alot.

Room temp is 22 degrees Celsius and humidity is on the dry side from 30-35%.

I will try more airflow and heat.

I didn't want to rebuild the whole ICC and it was an issue with airflow or heat etc.
 

Bly

New Member
Check out "coalescence" in that troubleshooting PDF.

I think there are a couple possible causes.
 

RobbyMac

New Member
Curious what material it is. We've been running into a similar problem with our avery 1005 and 1005 ez. It was happening randomly (One roll would print fine, the next not so much). We bumped the drying (preheat) up to 131 (pretty much maxxed) and its cured our problem at 10p...
 

BigfishDM

Merchant Member
Remember there are 2 heaters in the printer, dryer and curer and they do very different things. Most of e time that wet print people see is because the water in the ink that needs to be dried out at the first heater has not dried completely and there for the curing heater can not fully do its job. So the key on a media where you have a problem with overheating (usually something like polypro is what people complain about but it prints perfectly and stays totally flat).

Usually in this "wet" situation people make the assumption they need to increase the curing but this is generally wrong. First you need to look at the "wet" print and establish if it's cured or not by trying to smudge the wet part with your finger. If its not cured the sole print will wipe off to the white of the media under, but generally what you will see when you do this test is only a small amount of ink coming off on our finger but most of it stays behind. Tis means that the print did actually cure, but that the water from the ink was not properly dried out by the first heater

In this case, keep the curing at the same setting if it is not heat affecting the media at this point and make sure the drying heater is set to the maximum 55. If it wasn't that may have been the problem. There is a cheat on the drying heater to get it above the 55 by increasing the "minimum drying power" to something like 1.1 or 1.2 (never go over 1.2 though because you can actually overheat that zone and get an error from the printer, under 1.2 will be fine).

When you increase the minimum power setting you are forcing the drying heater to run hotter and when you actually print if you look at the printer it will be running much hotter than 55 actually and this can often resolve the problem also.

The last thing that it's important to understand that curing a print in a L25500 is like baking a cake- if you want your cake quickly so you heat up the oven really hot and take the cake out early then the outside of the cake will be burnt and the inside uncooked. To point of that example is to help people understand that sometimes a media needs to be printed on a slower pass mode to give the heaters time to fully work but at a lower temperature in the case the media can't accept the heat very well.

I have some customers that try the pass modes to see the quality differences (as you might on a solvent printer for example) but because of the drop technology and the OMAS along with head nozzle monitoring the printer is pretty much the same print quality at almost all of the print pass modes so they assume they should just run 8-pass bidirectional on everything and then complain because some media doesn't cure properly ir is heat affected

In my experience cast vinyl needs to be run at 12-pass with a curing zone no hotter than 103degC. The mesh banner runs at 10-pass bidir low ink, with dry-55, cure-110 and the PVC backing is fractionally harder to get off after printing but not enough to matter in any way
Most monomeric and polymeric vinyl is ok at 10-pass bidir dry-55, cure-110 but a high quality polymeric vinyl such as 3M IJ poly must run at 12 pass or it gets heat affected.

So the key in all of this is even a really heat sensitive media like a thin polypro (that many assume doesn't work on latex) prints absolutely perfectly with no heat affect at all but you may have to slow the printer down a fraction. This should never be any concern because an L25500 (just like a L26500 now) is still running much faster than any of it's competitors even when run at a slower pass mode on the problem media. And if they want to run the printer faster they need to use a better grade product such as a thicker polypro that will be less heat affected
 

dypinc

New Member
Curious what material it is. We've been running into a similar problem with our avery 1005 and 1005 ez. It was happening randomly (One roll would print fine, the next not so much). We bumped the drying (preheat) up to 131 (pretty much maxxed) and its cured our problem at 10p...

Avery I have some 2005 here that has that problem on the left side into about 3". The rest of it is fine.
 

RobbyMac

New Member
Avery I have some 2005 here that has that problem on the left side into about 3". The rest of it is fine.

We would notice the coalescence on the outside edges most times also. But when we moved the material to the right side, printing 54" material, it still would coalesce on the left even though it was bumped several inches inside the 'heater edge'. A few times we'd get the problem in the center of the roll.

The material however, would all print fine on our mimaki. So we experimented with adjusting the heat some.

our previous settings for 10p were:
Dry 122
Cure 230
Airflow 45
vac 20

We maxxed the heat for dry to 131 and so far so good...

We've spoken to our avery rep recently to let him know and we'll provide some samples to check out. It'd just a bit odd because this problem started showing itself within the past month or so. All last year we didn't run into anything like this, and we probably didn't even have our ink limits set half of that time.
 

HulkSmash

New Member
Avery I have some 2005 here that has that problem on the left side into about 3". The rest of it is fine.

that's averys big issue. They have partial contamination. I returned 5 rolls that had that issue. Some of the rolls had splotches throughout it. Ink wouldn't stick to it. Return the roll.
 

jasonx

New Member
Curious what material it is. We've been running into a similar problem with our avery 1005 and 1005 ez. It was happening randomly (One roll would print fine, the next not so much). We bumped the drying (preheat) up to 131 (pretty much maxxed) and its cured our problem at 10p...

Hey Robby this is 1005EZ as well.

I will try and set the drying tempreature higher to see if it alleviates the problem.

If it was a material contamination issue wouldn't we also have issues on our solvent machines? These rolls print fine on solvent just have this problem occurring on the latex.
 
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