PURPOSE: To print continuously to the end of a line and prevent a printing position from being shifted, by a method wherein the distance measured along an ink ribbon passage from a position corresponding to a printing head to a position corresponding to a detecting port is set to be at least the width over which the head is moved.

CONSTITUTION: The bottom of a cassette casing 1 is provided with the detecting port 10 for receiving light from a photoelectric ribbon end detector 9 provided on a carriage 8, and the end of an ink ribbon is detected at the position of the detecting port 10. The distance measured along the ink ribbon feeding passage from the position corresponding to the printing head 5 at an head opening part 6 to the position corresponding to the detecting port 10 is selected to be equal to or slightly larger than the width over which the piriting head of a printer or the like is moved. Accordingly, under various conditions of use, when the ribbon end is detected in printing in a line, printing can be securely continued at least to the end of the line.