Bad prints

That appears to be from dirt on the vinyl. Clean/check the vinyl squeegees. Is the environment generally clean or is there a lot of dust around? Also, are you buying full rolls or is your vendor rolling off vinyl to cut smaller rolls? They could be contaminating the vinyl when they do this if their process isn't clean.
When troubleshooting print issues on an Edge, I generally try things out with a roll of Gerber 220 or some other EdgeReady vinyl from Gerber. If the problem persists with Gerber vinyl, then you've eliminated one possible cause.

Good Luck

 

651 is not a great print vinyl. Yes you 'can' print on it, doesn't mean you should.

 

I just tell people to use the Gerber cleaning cards after they clean the head. Keep working outward with the cleaning card. I also use alcohol wipes from the drug store for general cleaning - these could be used on the squeegees, but not on the head. Or just isopropyl on a lint free rag.

 

What Joe House said. Also - I wipe the vinyl about to be printed on with a dry microfiber towel.
And 220 or 3M vinyl prints SO much better than 651. - smoother, no little pockets - just a better cast vinyl.
Also - that pattern of imperfection looks like it may have been adhesive from tape holding the roll together.

I keep all my vinyls stored in the plastig bags, on vinyl hangers.

 

Calendered vinyl has too many ripples, dimples, imperfections, etc. for EDGE work.

 

Although I agree this might apply to 651, I've found Avery 700/750 prints quite nice on the Edge. Definitely not as good as 220, but still works well. Just sayin'!

 

Was that perhaps your first run of the day? Or at least first print in a couple of hours? I’ve found now that my edge is a little older, it sometimes needs a bit of a ‘wakeup’... to get the head warmed up.

For that, I usually create an 11.8” x 3” rectangle to print. Everything prints flawlessly from then on.

3M SC50 works well for me when I’m printing on calendared vinyl. Colour selection is fairly limited, though.