looks to me that you have 2 main problems.
first problem is alignment look at the black line on the left that runs in the direction that the media feeds through the printer all those different colored lines need to line up on top of each other.
I have not owned a mimaki JV3 for awhile (JV33 now) but I do have a lot of the manuals on disk if you need them. you need to do an alignment for the Y that should fix that problem.
The second main problem looks like your magenta head is creating a lot of over spray this most likly (since you had to recover dried heads) means that you have a lot of nozzles that are spraying but are not spraying straight down but to the side. Try to recover it some more or you will have to replace this head to fix this problem (sorry for the bad news)
Also the second problem could be from the rip settings (and bad nozzles) Please post a pic of your nozzle check and give the details of what rip your using and what the settings are as we may be better equiped to help you if we know the details.
If your rip has a high quality mode uncheck or turn it off (my JV3 always oversprayed on high quality mode) you can also try running it slower and perhaps in uni direction if your printing in bi direction these probably wont fix the overspray problem but may make it a little better. also make sure the head height is set to low for regualr vinyl.
Again give the details of the rip ie... what rip, dpi, number of passes, bi or uni dircetion, high quality mode or not, etc etc... this will make it easier to point you to possible fixes.
But I believe that the nozzles are the biggest problem on the magenta overspray and I know a Y direction alignment will fix the black line problem.
If you are going to do an alignment please do yourself a favor and do every alignment procedure X, Y, media comp, etc at the same time and also take your time and get it dialed in the best you can ( the better the alignment the easier it is to figure out what is really going wrong).
