Troubleshooting
Calibrating a Zebra printer
Calibration is how the printer learns where your labels start. It is the fix for blanks, creeping prints and labels that stop in the wrong place — and the wrong fix for everything else.
What calibration actually measures
A printer finds the top of each label by watching its sensors as the media moves: a gap between die-cut labels, a black mark on the back, or nothing at all on continuous stock. Calibration feeds a couple of labels and measures what those sensors see, so the printer knows what a gap looks like on this roll.
Everything the printer does afterwards to position a label rests on that measurement. When it is taken against different stock than the one loaded, the printer is looking for the wrong thing — which is where blanks, creeping and short stops come from.
Set the mode before you calibrate
Calibration measures against the settings in force, so the media type and tracking mode have to be right first. Calibrating and then changing ^MN is the combination that produces the strangest results, because the measurement no longer matches what the printer is looking for.
- 1Set ^MT for the media: T for thermal transfer with a ribbon, D for direct thermal without one.
- 2Set ^MN for the stock: web sensing for die-cut labels with gaps, mark sensing for black marks on the back, continuous for a plain roll.
- 3Send ~JC to calibrate. The printer feeds a couple of labels and measures.
- 4Send ^JUS if the settings should survive a power cycle. Without it the printer reverts the next time it is switched off.
^XA
^MTT
^MNY
^JUS
^XZWhen calibration is the wrong fix
Calibration solves problems of position on correctly fed media. It does not solve a problem in the label, and reaching for it first wastes stock — every calibration feeds labels.
- A label that prints in the wrong place on stock that feeds correctly is a format problem: ^LH, ^PW or ^LL, not the sensors.
- A label that comes out blank but feeds correctly is a media type or darkness problem. Calibration does not change either.
- A bar code that prints and does not scan is a quiet zone, module width or print quality problem. The sensors have nothing to do with it.
Never leave ~JC in a label template. It runs on every print, and each run feeds labels — a calibration belongs in the configuration file that sets the printer up, sent once.
~JC and ~JL are not the same thing
~JC is the full calibration: it measures the sensors and works out what a gap or mark looks like. ~JL is the lighter one: it feeds a label, measures its length, and sets that.
~JL is what you want on continuous media, where there is no gap to find and the printer has no other way to know where to stop. After a media change where the gap or the liner also changed, ~JC is the one that is needed.
Open the ZPL viewer
Rule the label out before touching the printer: if it renders here at the size you expect, the format is not what is misplacing your print.
Open the ZPL viewerCommon questions
- How often should I calibrate?
- After a media change, after changing the media type or tracking mode, and when the symptoms above appear. Not on every label — each calibration feeds stock.
- Does calibration survive a power cycle?
- Only if the settings are saved. Send ^JUS after configuring, or the printer reverts to what it had the next time it is switched off.
- Calibration did not fix my problem. What now?
- Then the problem was not where the label starts. Check the format for ^LH, ^PW and ^LL if the position is wrong, media type and darkness if the label is blank, and the bar code's quiet zone and module width if it will not scan.