My experience with all Dymo printers is that the margins are drunk... All the time. Sometimes I've had luck by just removing the label roll, and putting it in again. Other times I adjust the barcode in a graphics editor to compensate for whichever margin is the drunkest at the time. That's a big let down when it comes to Dymo printers... There is no way to offset the margins/alignment or to set a custom page size.
Getting it right with a label that is only 1/2" wide can be frustrating. The easiest solution would be to shrink the size of your barcode so that it does not even come close to your Dymo's ambiguous page margins.
I've had limited success by fooling the Dymo into thinking that I'm using a different label roll than the one I am actually using. Say your label is 1.75" x .5"... If you can find another label template that is 1.75" x 1", tell the printer that you're using the bigger label, but actually, have the smaller label (30346) on the spool when you print... This would eliminate your left and right margins because the printhead is now going to print for a wider template, but since it's the same hight the sensor marks will still line up. That way you can effectively print edge-to-edge (You can do this with the top and bottom margins too, but it's a little trickier). It takes a bit of measuring and adjusting w/ your graphics editor, but it works if you've got the time to figure it out.
