Currently, we save as UTF-8 file and send to the printer. Can you edit files in c:\woopos\receipts folder in NotePad? Print directly from NotePad, then save the file as Unicode and print again. Some printers may not support Unicode in the text mode. Please test and let me know the result.
You can also try to install printer driver and print as graphics mode instead of text mode by “Generic / Text Only” printer. This will work for sure.