A printing apparatus is described, comprising: at least one pad comprising a cavity and a printing surface, a printing device adapted to form at least one image portion on the printing surface of the least one pad, pad moving means adapted to orient the pad in a first working position in which said image portion is formed in said printing surface of the pad by means of said printing device and in a second working position, different from the first working position, in which said image portion is imprinted on the object to be decorated by pressing the pad onto the object, further means adapted to act on the cavity of the pad to determine a flat shape of the printing surface of the entire pad in the first working position and a substantially convex shape of the printing surface of the entire pad in the second working position.