For Thermal Printer bulk label printing,
Need to download and install QZ printer utility updated (2.0.9 ) for printing ZPL labels. Use this file (Click Here) to setup for print invoice & labels via a thermal printer.
You can use the below thermal printer setting’s parameters so it will give you seamless label prints.
1- Automatically Start: Check
2- Under Advanced > Block anonymous requests: Uncheck
3- In the pop up window: Allow: Check (with remember selection)