PURPOSE: To eliminate the slack of an ink sheet by constituting the recorder that the ink sheet is folded into an angle shape by a platen roller when an original platen is closed.

CONSTITUTION: A cassette accommodating the ink sheet 1 is fitted attachably and detachably to the original platen cover 17 and a thermal head 3 is placed to the upper side of the ink sheet 1. On the other hand, the platen roller 4 in contact with the thermal head 3 is provided to the main body via the ink sheet 1. The relation of position between the thermal head 3 and the platen roller 4 is set that the ink sheet is folded into an angle form by the thermal head and the platen roller when the original platen cover 17 is closed. Through the constitution above, even if the ink sheet has slack, since it is removed automatically by closing the original platen cover, the missing of a picture based on the slack of the ink sheet is prevented.