Need Help Consistent dark dots when printing on fabric with an HP FB750

[Andrew Hodgson]

Hello, I am trying to print on fabric with my HP FB750. I have tried several sample rolls of various fabrics that work with a UV printer. Most of the time the graphic looks good, but sometimes, part of the graphic will have a grid-like effect with dark round dots. I have attached an image where you can see the round dots, and another image later on in the print where you do not see it. I feel like it has something to do with the vacuum on the printer bed.

I think this usually happens at the beginning of the print or when the graphic has a solid break from color to white.

 

[flyplainsdrifta]

it looks like the holes on the belt, but hard to say. if youve had any misses with board or banner previously and you have ink in those holes, when the vacuum pulls it down it may be transferring from there. not sure, shot in the dark. does it repeat in the same spot incrementally or is it completely random?

 

[Andrew Hodgson]

it looks like the holes on the belt, but hard to say. if youve had any misses with board or banner previously and you have ink in those holes, when the vacuum pulls it down it may be transferring from there. not sure, shot in the dark. does it repeat in the same spot incrementally or is it completely random?

I agree and think this happens where the holes on the print bed are. I am not sure if it happens on the same place on the belt but the spot distance between them all are the same which is why I think it has something to do with the belt.

But the areas that it happens in can be 12" x 12" or so and I have never overprinted onto the built with that large of an area. Most of my overprints are at most a .25" line on the printer belt.

 

[pkeshtgani]

Had the same issue. You need to decrease the fan suction. But at same time if you do that the fabric might not be able to move forward