PURPOSE: To prevent an extra ink from sticking to paper and improve durability by forming an annular protrusion with an external diameter slightly larger than that of a type part in the type part of a printing wheel and forming an annular recessed part against the annular protrusion in an ink-impregnated roller.

CONSTITUTION: If a printing wheel 1 is rotated to select characters to be printed, the first and second ink-impregnated rollers 7, 12 rotate following a contact friction. Consequently, ink is supplied to a type part 2 from the first ink- impregnated roller 7, replenishing ink to an ink-impregnated element 9. After this, paper 5 is supported and kept afloat by an annular protrusion 3, and a printing hammer 6 is driven to perform printing. The ink-impregnated element 9 contacts only the type part 2, so that no ink is supplied to an extra part of the printing wheel 1 and, subsequently, to extra ink sticks to paper 5. The annular protrusion 3 sticks out of the type part 2. However it protrudes into the annular processed part 11 of the ink-impregnated roller 7, not allowing prevention of an ink supply action from the ink-impregnated roller 7 to the printing wheel 1.