Perhaps UTF-8 is not supported as a character set/code table.
Even EPSON is supported only on some models.
FS ( C <Function 48>
Select character encode system
ASCII FS ( C pL pH fn m
Hex 1C 28 43 02 00 30 m
Decimal 28 40 67 2 0 48 m
TM-P20
1, 49 ASCII (ISCII) ISCII: Indian Script Code for Information Interchange
2, 50 UTF-8 Unicode encoding system
TM-m30II, TM-m30II-H, TM-m30II-NT
1, 49 1-byte character encoding Non-Unicode encoding method (ASCII [extended], Shift JIS, Big5, GB2312, GB18030, KS C, etc.)
2, 50 UTF-8 Unicode encoding system
You need to set the printer code page using the following two ESC/POS commands, and the character string to be requested for printing must be encoded and converted according to the code page before sending.
ESC t
Select character code table
ASCII ESC t n
Hex 1B 74 n
Decimal 27 116 n
ESC R
Select an international character set
ASCII ESC R n
Hex 1B 52 n
Decimal 27 82 n
Alternatively, you can create all the page contents to be printed with a Bitmap image and print it with one of the ESC/POS commands related to image printing.
However, it will be slow.