To eliminate an inconvenience of deforming a ribbon separator when a print sheet is replaced by an arrangement by fixing a magnetic body to the upper part of the ribbon separator and a magnet to the hammer bank side such that the ribbon separator can be opened only when an ink ribbon is replaced.

A hammer mechanism section comprises a hammer bank 5 including a plurality of print hammers, and a ribbon separator 11, and the like, for preventing inadvertent transfer of ink from an ink ribbon 3 to a print sheet 2 being carried by means of a tractor 6. A magnetic body 8 is fixed to the upper end part of the ribbon separator 11 and a magnet 9 is fixed to the facing hammer cover 4 side. Since the hammer cover 4 is closed under a state where a platen 7 is opened, the magnetic body 8 is attracted by the magnet 9 to hold the ribbon separator 11 in closed state thus eliminating an inconvenience of damaging the ribbon separator 11 when the print sheet 2 is replaced.