Troubleshooting thermal label printing in Breww

Use this guide when a stock label, delivery label or permanent keg label generated by Breww does not print correctly on a dedicated thermal label printer, such as the Zebra ZD421t.

This guide does not cover A4 or US Letter label sheets, such as Avery labels printed on a normal inkjet or laser printer.

Check the PDF first

Before changing anything on the printer, open the label PDF and check that it looks correct on screen.

Make sure:

• The expected information is present.

• Everything fits on one label.

• Nothing overlaps or runs off the edge.

• The PDF is not blank.

• You selected the version for a thermal label printer, rather than the A4 or US Letter sheet version.

The PDF does not look right

Changing the printer will not fix a problem already visible in the PDF.

If you are using a custom stock label template, check that its contents fit correctly on one label. You may need help from the person or developer who created the template.

Custom templates are only available for stock labels.

If you are not using a custom stock label template, contact the Breww support team through Need help? and include the affected PDF.

The PDF looks right

Continue below. The problem is likely to be with the printer, labels, ribbon or print settings.

Check the setup for the label you are printing

Parts referred to in this guide

The image below shows an empty Zebra ZD421t. The label roll, ribbon and empty ribbon core have not yet been fitted.

Choose the problem

The label comes out completely blank

Check how the labels are loaded

Open the printer and make sure:

• The printable side faces upwards.

• The roll sits straight between the yellow arms.

• The labels pass underneath both label guides.

• The guides lightly touch the sides without squeezing them.

• No label has peeled off and become stuck inside the printer.

Stock and delivery labels

These should normally print:

• Without a ribbon

• Using Direct Thermal

  Check that:

• Any ribbon has been removed.

• The printer is set to Direct Thermal.

• The label packaging says Direct Thermal or DT.

  If you are unsure, scratch the printable side firmly with a fingernail:

• A dark line appears: the labels are direct thermal.

• No dark line appears: the labels probably require a ribbon.

Permanent keg labels

These should print:

• With a ribbon

• Using Thermal Transfer

  Make sure:

• The new ribbon roll is fitted in the lower ribbon position.

• The supplied empty cardboard core is fitted in the upper position.

• The ribbon runs underneath the printhead.

• The ribbon is attached to the empty core.

• The ribbon is flat and not loose or heavily wrinkled.

• The inked side faces down towards the labels.

  The shinier side usually faces upwards. The duller side usually contains the ink.

  If you are unsure:

1. Press clear sticky tape against one side of the ribbon.

2. Peel it away.

3. Check whether black material transfers onto the tape.

4. Test the other side if necessary.

   The side that leaves black material on the tape must face the labels.

Close the printer properly

Press firmly on both front corners until both sides click shut.

Try printing again.

If the label is still blank, go to Test the printer without using Breww.

The print is faint, patchy, blurred or smudged

Check that:

• Both sides of the lid are fully closed.

• The labels are running through the printer straight.

• The label guides are not pinching the labels.

• The ribbon is flat and tight when printing permanent keg labels.

• The ribbon covers the full width of the label.

Clean the printhead

The printhead is the dark strip inside the upper part of the printer.

1. Turn the printer off and allow it to cool.

2. Open the printer and remove the ribbon, if fitted.

3. Clean the printhead using a suitable printhead cleaning pen.

4. Wipe from the centre towards each side.

5. Allow it to dry before reloading the printer.

   Do not scrape the printhead or touch its printing surface.

Adjust the print quality

In the Zebra printer settings:

• If the print is faint, increase the darkness slightly.

• If it is smudged or too dark, reduce the darkness.

• If it remains faint, reduce the print speed.

  Change one setting at a time and print another label.

  If the same vertical white line appears on every label after cleaning, the printhead may be damaged.

The printed label does not match the PDF

This includes labels that are:

• Cut off

• Too large or too small

• Rotated

• Spread across several labels

• Starting in the wrong place

Check the label size

The size selected on the computer must match the labels in the printer:

• Stock and delivery labels: 102 × 76 mm

• Permanent keg labels: 51 × 25 mm

  Check the size in:

• The Zebra printer settings

• The final print window

• Printing Defaults on Windows, where available

Check the final print window

Before printing, make sure:

• The correct Zebra printer is selected.

• The correct label size is selected.

• Scaling is set to 100% or Actual size.

• Fit to page is turned off.

• Shrink to fit is turned off.

• Margins are set to none or zero.

• Pages per sheet is set to one.

• The correct orientation is selected.

  If the label is rotated, switch between portrait and landscape.

  Change the rotation in one place at a time.

  If the label starts in a different position each time, continue to The printer skips labels or keeps feeding them through.

The printer skips labels or keeps feeding them through

The printer may not be detecting the gap between one label and the next.

Check the labels

Make sure:

• The roll sits straight.

• The labels pass underneath both guides.

• The guides lightly touch each side.

• The strip the labels are stuck to lies flat.

• No labels are missing from the roll inside the printer.

Check the label setting

For labels with gaps between them, choose a setting such as:

• Gap

• Web

• Gap/Notch

• Non-continuous web

  Do not select Continuous unless there are genuinely no gaps or marks between the labels.

Calibrate a Zebra ZD421t

1. Load the labels and ribbon, if needed.

2. Close the printer.

3. Turn it on and wait for the green ready light.

4. Hold Pause and Cancel together for two seconds.

5. Release both buttons.

   The printer will feed several labels while it measures them.

   When it finishes, press Feed once. The printer should move forward by one label and stop.

   If it skips every second label, also check that:

• The selected label height matches the roll.

• The PDF does not contain a blank second page.

• Pages per sheet is set to one.

The printer does not respond

Check the printer

Make sure:

• It is switched on.

• The green ready light is showing.

• The lid is closed.

• Labels are loaded.

• A ribbon is fitted when printing permanent keg labels.

• The printer is not paused.

• No label is jammed inside it.

  Press Feed once:

• If one label moves forward, the printer itself is responding.

• If nothing happens, restart the printer and check the lights for an error.

Check the computer

• Make sure the correct Zebra printer is selected.

• Open the list of waiting print jobs and remove any failed or stuck jobs.

• Make sure the printer is not shown as paused or offline.

• Restart the printer and computer.

  For a USB printer:

• Unplug and reconnect the cable.

• Try another USB port.

• Avoid using an unpowered USB hub.

  For a network printer:

• Make sure it is still connected.

• Check whether its network address has changed.

  If several similar Zebra printers appear, try each one to find the entry that controls the physical printer.

The problem started after changing labels or ribbon

When switching between stock or delivery labels and permanent keg labels, you may also need to change the ribbon, printing method, label size and calibration.

Changing to permanent keg labels

1. Load the 51 × 25 mm permanent labels.
2. Install the ribbon and empty ribbon core.
3. Make sure the inked side faces the labels.
4. Select Thermal Transfer.
5. Set the label size to 51 × 25 mm.
6. Calibrate the printer.

Changing to stock or delivery labels

1. Load the 102 × 76 mm temporary labels.

2. Remove the ribbon.

3. Select Direct Thermal.

4. Set the label size to 102 × 76 mm.

5. Calibrate the printer.

   If the previous printing method keeps returning, check both the saved Zebra settings and the final print window.

Test the printer without using Breww

Use this step if the earlier checks have not resolved the problem.

Print a printer test report

1. Load the correct labels and ribbon.

2. Close the printer.

3. Turn it on and wait for the green ready light.

4. Hold Feed and Cancel together for two seconds.

5. Release both buttons.

   The report may use several labels.

The report prints correctly

The printer, labels and ribbon are working.

Recheck:

• The PDF

• The selected label size

• Scaling

• The selected printer

• The browser or app used to open the PDF

The report is blank or poor quality

Recheck:

• The type of labels

• Which way the labels face

• Whether a ribbon is required

• Which way the ribbon faces

• Direct Thermal or Thermal Transfer

• Whether the lid is fully closed

• Whether the printhead needs cleaning

  Try a fresh compatible roll of labels and a fresh ribbon where possible.

The report skips labels or keeps feeding them through

Repeat the checks and calibration in The printer skips labels or keeps feeding them through.