Toshiba B-EX4T1-G/T Operation Manual page 62

[Format...]
The specified range of the specified memory is formatted.
When this button is clicked, the following message is displayed.
When [Yes] is clicked, the processing starts.
When [No] is clicked, the processing is canceled.
When the processing starts, the progress status screen is displayed. When the processing is
completed, the completion screen is displayed.
This function is executed only when the printer is in the TPCL or TPCL1 mode and in the idle state.
This Product waits for the end of memory format after sending a Flash Memory Format command to
the printer.