Usually this is a physical problem caused by the printer sensor or the printing material. It could also be a problem related to the printer drivers. Here are a few suggestions on what might be happening and things you can check:
- The printer sensor must be clean and has to be placed at the center of the label.
- Make sure the printer is calibrated.
- If the printing speed is very high, you can try to print with a lower speed and see if there are any changes.
- In some cases it's not a physical problem of the printer, and using a different printer driver can solve the issue.
- Old or damaged label rolls have been known to cause printers to skip labels.