Weird effect when printing banner materials on HP Latex 365

[Ronny Axelsson]

I’ve been using an HP Latex 365 for some years now and have noticed a strange effect when printing on structured PVC banner materials.

At first, the prints look great, with dark areas like black coming out perfectly, but after about 120 to 150 millimeters, white spots suddenly appear in those areas.
It seems like the ink no longer reaches the bottom of the textured surface, and the change happens abruptly with a sharp edge that’s easy to see.
It doesn’t matter if I start near the end of the roll or feed a meter before printing.
If heat from the curing unit were the cause, I’d expect the transition to be more gradual.

Has anyone else experienced this?

 

[balstestrat]

Plasticizer migration on the surface. Clean with surface cleaner and try to print -> if it works it's faulty roll.
If surface cleaning makes no difference -> optimizer printhead is not working.

That's all there's to it.

 

[Ronny Axelsson]

Optimizer, both ink and printhead are almost new so I doubt that's what causing it.
Maybe I could try increasing the optimizer level in the profile?

Plasticizer maybe, but why does it suddenly start after a short distance, every time?

 

[JBurton]

Plasticizer maybe, but why does it suddenly start after a short distance, every time?

It's just the difference of the wet ink vs dry. When it's drying it's sticking to the uncontaminated areas, and wicking away from the plasticized bits. Try cleaning a section with alcohol and running a test print on that area.

 

[Ronny Axelsson]

I will give it a try as soon as I get the time.
Thank you guys.