PURPOSE: To obtain a compact smudge preventing mask, in a ink applying type printer, by engaging a positioning member comprising a material whose linear expanding coefficient is different from that of a frame with the smudge preventing mask which is supported on the frame by a shaft.

CONSTITUTION: The smudge preventing mask 6 has the tips which form comb teeth shaped smudge preventing parts 6a and the parts are positioned in the grooves between type rings 2aW2a of a type dum 2. Bent parts 6b at the lower end are rotatably supported by supporting parts 1a of the frame 1. The mask positioning member 7 comprising e.g. a plastic material whose expansion coefficient is larger than that of the frame 1 is engaged with the top of the bent part 6b through a pin 8. The other end of the positioning member 7 is fixed to the frame 1. When the temperature is increased, the member is elongated and operated so that the smudge preventing part 6a of the mask 6 is separated from the type drum 2, and the increase in the quantity of the ink applied to the type drum 2 from an ink roll 3 is prevented.