To solve such problems that when an air knife mechanism with a separating claw is used with a plurality of printing drums, the uniform separation of printing ink cannot be achieved depending upon the extent of a printed image area and consequently, image density irregularities tend to occur and when the printing paper is conveyed in such a state that it is rather curled, the positional deviation of a first and a second color printed image, for example, ensues.

This multi-color printing device comprises hold-down rollers 11a-11d for pressing the printing paper 32 on an impression cylinder 6 to the outer peripheral face of the impression cylinder 6 at the outlet side of a nip part between the printing drums 1a-1d and the impression cylinder 6, hold-down roller displacing means 12a-12d for displacing the hold-down rollers 11a-11d, roller interval varying means 23a-23d and a control means 25.