Recently, I was testing out the epson-multi-tone project by dalpil on my TM-T88V and noticed it slowed down the speed of the printer. After checking the code and the Epson command reference, this is achieved by GS ( K, function 50. This is the documentation for it.

It works on the TM-T88IV through VII and many others shown in the documentation.

You can set it like this:

print_speed = bytes([0x1d, 0x28, 0x4b, 0x02, 0x00, 0x32, 0x00])
#                     GS    (     K    parm-length  fn    spd
# This byte sequence would set the print speed to the default.

printer._raw(print_speed) # send bytes to printer

Epson documents speed levels 0x01 (slowest) through 0x17 (highest) but in my testing, any speed after 9 produced no discernible increase. Setting the speed to 0x00 resets it to the default, which I think obeys DIP switch configuration of the printer.

Oddly, setting the default seems to have the fastest speed, even faster than setting speed level 17 via this command. This might be because my printer has the DIP switches set for the fastest possible print speed.

It would be nice if python-escpos could set the speed of the printer with the set() method. Also resetting it via set_with_default() would be really nice too.