Image Number 7 for United States Patent #6202558.
An apparatus for reducing procession of a gapless tubular printing sleeve in an offset printing press caused by at least one fluid wave having a certain pressure trapped at an interface of the printing sleeve and a cylinder on which it is mounted. The apparatus includes a cylinder which is adapted to receive the printing sleeve for mounting on its circumferential surface. The cylinder has at least one path which connects an interface of the cylinder and the printing sleeve to a region of pressure lower than the pressure in the fluid wave. The path allows the fluid wave, which is trapped at the interface and advancing in front of a nip between the cylinder and an adjacent cylinder, to escape to the region of low pressure.