To ensure the gap sensor detects the space between labels when printing labels on an Eltron or Zebra printer, execute the following command from the printer driver to force the GAP sensor to check for the label spacing.

There is a way to have the Zebra TLP2844 printer recalculate the gap sensor, that should work for many of the other zebra models as well. It is to turn off the printer, then turn it back on while holding the Feed button. You need to let go of the feed button as soon as the light starts flashing red. The printer will do a bunch of feeding and detecting of the gaps. This will fix some problems up.