Thermal transfer printer and ink ribbon cassette for use in transfer printer

A ribbon cassette mounted detachably with respect to an upper surface of a carriage of a thermal transfer printer, said thermal transfer printer having a plurality of detection switches arranged along a straight line on said upper surface of said carriage for detecting the presence of the ribbon cassette and for determining a type of ribbon stored in the cassette, said ribbon cassette comprising:

• a case including parallel side walls, a back wall extending between said side walls, and a bottom wall;
• a feed reel and a take-up reel rotatably mounted in said case;
• an ink ribbon trained between said feed reel and said take-up reel;
• and
• a detection section including a plurality of detection holes formed on said lower wall of said case for engaging said plurality of detection switches disposed on the upper surface of the carriage of said thermal transfer printer, said detection section being formed at a position corresponding to an outermost circumference of a wound diameter of the ink ribbon wound on said take-up reel and said feed reel, said plurality of holes of the detection section being arranged diagonally with respect to the back wall and the side walls of the case such that the detection section aligns with the plurality of detection switches disposed on the upper surface of the carriage.