HP L115 Printing on oil-slick vinyl

[BlackHatPrinter]

Hey everyone, long-time lurker, first-time poster.

I've been testing out various types of vinyl to up my sticker game.
For the oil slick vinyl I'm using, I've been encountering a "spotty" print, but it doesn't look like it's ink that's been scratched off by the print head or anything either.
It seems to happen more noticeably for the black areas. Does anyone know what might be causing this and how to get rid of it?

This vinyl also seems to curl a lot more than other oil slick vinyls..

Before I go waste more material, my theory on fixing it is:
1. Lowering the curing temperature to reduce curling.
2. Then increasing number of passes to "fill blank spots" (currently at 8 passes).

Thank you in advance!

 

[ikarasu]

Does it even adhere? Put a small piece of tape on it and see if it comes off.

What vinyl is it? Printable at all? My guess is it's not a printable so there is no coating which leaves the spots. Most specialty vinyls don't like heat unfortunately... So I'd try to go higher passes, lower heat and see if that helps.

 

[balstestrat]

Looks like bad material with plasticizer migration issue.
You can verify that by cleaning a part of it with ipa and then printing on it.
If it's plasticizer it wont help to increase passes. Only helps to change roll.

 

[BlackHatPrinter]

Does it even adhere? Put a small piece of tape on it and see if it comes off.

What vinyl is it? Printable at all? My guess is it's not a printable so there is no coating which leaves the spots. Most specialty vinyls don't like heat unfortunately... So I'd try to go higher passes, lower heat and see if that helps.

It does adhere! It doesn't scratch off and seems to stay even with packaging tape being ripped off of it.

 

[BlackHatPrinter]

Looks like bad material with plasticizer migration issue.
You can verify that by cleaning a part of it with ipa and then printing on it.
If it's plasticizer it wont help to increase passes. Only helps to change roll.

I'll definitely try that.
I did think maybe it has to do with the warping from curing -- which might cause some ink migration especially before it's fully dry and set

 

[balstestrat]

I'll definitely try that.
I did think maybe it has to do with the warping from curing -- which might cause some ink migration especially before it's fully dry and set

Unlikely. Optimizer keeps it in position until cured.
You still clearly have sharp edges which means the ink stays where it should.