Patent ID: 8313260

Claim:
A device for compensation for variation of width of a flexible printing substrate ( 1 ), in sheet or strip form, that passes, in a multi-color printing machine, between generally rotating printing means that are organized in form of successive printing units (G 1 , G 2 , G 3 , G 4 ), by means of a directed air flow toward the printing substrate ( 1 ) for the purpose of modifying the printing substrate's surface evenness, the device comprising: at least one pair of deflectors ( 2 , 2 a , 2 a , 2 c ) that are arranged symmetrically on both sides of an axis (X) along which the printing substrate ( 1 ) passes, each deflector comprising an air-blowing chamber ( 6 ) that empties onto a deflector surface that is rotated toward the printing substrate ( 1 ) and that is oriented in a direction toward a rear of the deflectors in a direction (D) in which said substrate passes, so as to produce an air flow in form of an air knife for the purpose of facilitating, in parallel, the separation of said substrate from the surface of the deflectors and the accompaniment of the entrainment in movement of said printing substrate ( 1 ), wherein the deflectors ( 2 , 2 a , 2 a , 2 c ) are formed, in the direction (D) in which the printing substrate ( 1 ) passes, by a front part ( 4 ) and a rear part ( 5 ) that are mounted on a base ( 3 ), whereby a rear face of the front part ( 4 ) and a front face of the rear part ( 5 ) form walls of the blowing chamber ( 6 ), and wherein the blowing chamber ( 6 ) also comprises longitudinal walls formed by blocks ( 15 ) positioned between the front part ( 4 ) and the rear part ( 5 ) of the blowing chamber ( 6 ), the blocks ( 15 ) for adjusting spacing of the transverse walls relative to one another.