depending on the image these “frames” sometimes come up, when the file was saved in RGB instead of CMYK.
It’s also possible for the file to have some lightly colored outlines, so the printer is backing that up with white toner.
To get around this you can try using the “underfilling” feature in Step 4 of 5 (White Control)
With the feature „Underfilling“ you are able to delete 1-4 pixels around your design. With this option you can avoid the bleeding of colors or white edges (with pixel graphics) with only one click. Usually 1 pixel underfilling is enough.
Here’s a link to the RIPs Wiki page: http://systemata.synology.me/dokuwiki/doku.php?id=en:ns_sys_transfer-rip:weissauftrag_bestimmen
If that does not help, you can send us the original file, so we can take a look.
FOREVER Tech Support