PURPOSE: To improve the efficiency in the operation by comprising a raster roller located on an operating position where a joint can be separated from a driving shaft during the operation of an flexographic press, and a raster roller located on a reserve position and automatically exchangeable during the resting period of a press mechanism.

CONSTITUTION: A strip paper 22 is guided to a rubber coating tension roller 34 through a turning roller 32. The strip paper 22 is wound on a left cylinder 24 at the back of the tension roller 34, and the printing is performed thereon by the ink transferred from a raster roller 18a located on an operating position to a printing band 10 when the paper is passed between a support cylinder 12 and an impression cylinder 24. The raster roller 18a on the operating position and the raster roller 18b on the reserve position are mounted on two oscillating arms 38 existing in front of the raster rollers, and the oscillating arms are mounted on a cross beam of a machine frame 30 and are rotatable on a rotary shaft 36 existing at a center. The raster roller located on the operating position, is exchanged for the raster roller on the reserve position by the 180° rotation of the oscillating arms 38.