A jumping device for on-line cold ironing of a printing machine

The invention discloses a leafrogging device for on-line cold foiling of a printing machine. The leafrogging device comprises an unwinding device, a winding device, two anilox rollers and four groups of driving mechanisms, wherein the unwinding device and the winding device are used for unwinding and winding alumite foil respectively; the anilox rollers are arranged on the pathways that the alumite foil enters and leaves a printing unit respectively, and are arranged between the two side wall plates of the printing machine; each end of the anilox rollers is connected with one group of driving mechanism; the anilox rollers can slide along guide grooves, which are in the two side wall plates of the printing machine, under the driving of the driving mechanisms. The leafrogging device utilizes the characteristic that a roller is free from printing in a neutral position, adopts reciprocating movement of the anilox rollers to control conveying resulting velocity of the alumite foil, and improves usage rate of the alumite foil, that is, cost is reduced effectively and environment is protected while realizing on-line cold foiling; a key part adopts a cam mechanism; the structure is simple; operation is stable.