Need Help HP Latex 335 White Spots on Prints

[RustyNZ]

Hi,

Have a customer with a HP Latex 335 (I don't know much when it comes to latex) and they are having issues printing on one type of media, Orajet 3162. They get white spots which seem most noticeable in darker areas (maybe because they are white), these don't look like contaminants to me, not the standard dust on media anyway. If she prints the same thing on some Orajet 3551 it works fine and other medias seem ok.

I saw some mention of optimizer sometimes causing this issue, in the calibration sheet the - one was much worse but maybe I need to tweak it more subtley? The double optimizer one looked just as bad.

I've tested the same roll on an eco-solvent and it does not have the issue. This has happened on several different rolls from different batches and also has not happened on some rolls but has on her 3 most recent.

I did a calibration sheet, at least part of it anyway and it has the dots on there too. She is using a 3164 profile which should suffice as it's the same face stock, also tried a 3551 profile and some other one she created. There is also a mottled appearance sometimes too.

Seems odd it only appears on the latex not the ecosol using the same roll that had the issue. Does anyone have any suggestions here or have seen anything similar happen? Thanks for helping.

Edit: Now with attachments.....duh!

 

[greysquirrel]

if the roll is older it could be plasticizer migration... not a whole lot you can do. To test if its the media, clean a section with isopropyl alcohol then print on it after it dries...

 

[RustyNZ]

if the roll is older it could be plasticizer migration... not a whole lot you can do. To test if its the media, clean a section with isopropyl alcohol then print on it after it dries...

Doh, forgot to try that while I was there. Thanks for the suggestion, I'll see if we can get that tested.

 

[jasonx]

I've seen the issue as well.

 

[dypinc]

This is not good. I have seen this an awful of lot of late. Makes me think a lot of these brands use the same manufacturer. General Formations is so bad I had to quit using all their vinyls except for some reason I have not seen it yet on the regular 201. I even had some HP Grip that is showed up on. Sometimes I wonder if HP changed something in their ink.

 

[McLain]

Seems odd it only appears on the latex not the ecosol using the same roll that had the issue.

I would guess that this is some type of "oily" chemical contamination. Latex being a water based ink would have a problem (oil and water don't mix) but a solvent ink most likely would not have a problem since solvent based inks are made with "oily solvents."

The vinyl itself is a petroleum based product, so that contamination could be the plasticizer migration as mentioned above or something as silly as tiny droplets of an air freshener that was sprayed in the room that settled on the roll. Or perhaps the rolls were manufactured in an environment where some type of "oily air contaminant" was present.

I looked at the technical spec sheet from Orafol for this product and they do list latex ink as acceptable for this product, so I would imagine they would have controls in place in the factory to prevent any type of oily contaminant, but who knows, maybe some machine is malfunctioning.

 

[jasonx]

I think its plasticizer migration. We have the 570s with the wiper roller mostly used for banners with plasticizer migration. Using this wiper on these rolls seems to fix the issue mostly. So I don't think its oil. Its either an issue during manufacturing or we're receiving older stock. At first, I think it was my printers, rollers room environment. What's weird is we don't experience with all types mostly just the monomeric 316X.