Understanding Backfeed on ZPL Printer
A frequent question is how do the Zebra ZPL printers use backfeeding. This is
mode dependant and can set via the front panel or ZPL command (~JS) Details of
the ~JS command can be found in the
ZPL Programming
Manual.
The Modes are detailed below:
Backfeed After:
When in tear off mode, we will backfeed the very first label, and only the first
label. We will then print the balance of the batch with no backfeed.
When in rewind mode, we do not backfeed. This is similar to the tear off
position. This is not adjustable in rewind mode. If a PAX user is using rewind
there is a reason for this. They are trying to increase their application speed,
and do not want to backfeed, as this takes time.
When in applicator mode, we will backfeed each and every label. The reason for
this is that when we are set to backfeed after, the printer/print engine does
not know what the next label format is going to be, so it will backfeed every
time to make sure it prints the entire label format.
Backfeed Before:
When in tear off mode, we will backfeed the very first label, and only the first
label. We will then print the balance of the batch with no backfeed.
When in rewind mode, we do not backfeed. This is similar to the tear off
position. This is not adjustable in rewind mode. If a PAX user is using rewind
there is a reason for this. One of them could be that they are trying to
increase their application speed, and do not want to backfeed, as this takes
time.
When in applicator mode, we will backfeed only if we are required to print on
the leading edge of the label. The reason for this is that when we are set to
backfeed before, the printer/print engine knows what the next label format is
going to be, so it will backfeed if it is required to do so. This is where our
smart backfeed comes into play. If we do not need to backfeed, we will not. To
test this, have the customer modify their top position in the front panel to
move the printed image to the leading edge of the label. They should now see it
backfeed. Remember, our printhead elements on the printhead are located roughly
a quarter inch back from our peel bar. This is the area that is affected. If we
are required to print in this area, we will backfeed. If we are not, then no
backfeed is necessary.