If your printer always prints some empty labels before it starts printing your PDF files as the image below, in our experience, this issue is usually caused by:
Paper sensor malfunction.
We do not support the label paper.
The best approach is to seek assistance from your printer manufacturer since the issue is primarily relates to firmware and hardware.
For example, the ZEBRA 2.2" X 0.5" 8000T JEWELRY LABEL is unsupported because the printer driver does not support printing PDF format on particular model.