Printing barcode labels without misalignment
A barcode that looks perfect on screen can print shifted, shrunk or cut off. Almost always it is a print setting, not the barcode.
A4 sheets or thermal rolls?
| A4 sheets | Thermal rolls | |
|---|---|---|
| Printer | Office laser or inkjet | Thermal label printer (Zebra, Brother, Dymo, Rollo and others) |
| Best for | Tens to a few hundred labels now and then | Regular printing, one at a time or in bulk |
| Advantage | No extra hardware | No ink, one label at a time, no sheet alignment |
| Drawback | Part-used sheets are awkward to reuse | Buying the printer |
On a part-used sheet, enter the number of labels already used in the generator: printing starts at the first free label.
Printing on A4 sheets
- Scale 100 % (“actual size”). Turn off “Fit to page” or “Shrink oversized pages”.
- Margins: none in the browser’s print dialog.
- Paper size A4, not US Letter: a printer left on Letter shifts every row.
- Paper type “labels” or “heavy paper” if your printer offers it.
- Test on plain paper: print a page and hold it against a label sheet in front of a window. If everything is offset by the same amount, the printer feeds with an offset; if the offset grows towards the bottom, the scale isn’t 100 %.
On an inkjet, let the ink dry for a few minutes before handling the labels: a smudged barcode scans badly.
Printing on thermal rolls
- Set the label size in the printer driver (printing preferences), in millimetres, exactly as in the generator. Forgetting this is what causes blank labels between prints.
- Choose the media type: direct thermal (no ribbon) or thermal transfer (with ribbon), and labels separated by a gap or by a black mark.
- Calibrate the sensor after every roll change. On many models, a long press on the feed button starts calibration.
- Enter the resolution (203 or 300 dpi) in the generator so bar widths are rounded to whole dots.
- In the browser’s print dialog, select the thermal printer, scale 100 %, margins: none.
If every other label comes out blank, the driver’s label size is larger than the label. If the barcode is cut off or shifted down, the sensor isn’t calibrated.
Keeping a PDF
To send the labels to a colleague or reprint later, choose “Save as PDF” instead of a printer. The PDF keeps the exact dimensions; when reprinting, the same rules apply: scale 100 %, margins none.
Before the full run
Print a single label or sheet, scan it with the equipment you will actually use, and compare the value read with the code entered. If something is off, see barcode not scanning.