초록 ▼

A lithographic sheet-fed press having an impression cylinder with a gap formed in the surface thereof and having a cooperating blanket cylinder having bearers at its ends. A pair of auxiliary short bearer members bridge the gap in the impression cylinder, presenting arcuate edges for engagement with

A lithographic sheet-fed press having an impression cylinder with a gap formed in the surface thereof and having a cooperating blanket cylinder having bearers at its ends. A pair of auxiliary short bearer members bridge the gap in the impression cylinder, presenting arcuate edges for engagement with the bearers on the blanket cylinder, the bearer members are arranged at such radial height that when the blanket cylinder rolls into the region of the gap the force of printing pressure between the cylinders is taken over by the auxiliary bearer members to maintain the transaxial pressure between the cylinders substantially constant throughout the revolution thereby avoiding the cyclical impact accompanying sudden build-up of printing pressure at the end of the gap. The bearer members are guided for adjusting movement in a generally radial direction along precisely parallel paths to achieve corresponding settings to preserve the condition of constant pressure upon making a change in the thickness of the sheet stock being printed.

대표청구항 ▼

In a lithographic sheet-fed press having an impression cylinder with a gap in the surface thereof defining the printing area and a cooperating blanket cylinder having bearers at its ends, blankets on the cylinders establishing printing pressure therebetween as the cylinders rotate in engagement with

In a lithographic sheet-fed press having an impression cylinder with a gap in the surface thereof defining the printing area and a cooperating blanket cylinder having bearers at its ends, blankets on the cylinders establishing printing pressure therebetween as the cylinders rotate in engagement with one another, a pair of auxiliary short bearer members arranged to bridge the gap in the impression cylinder, said bearer member presenting arcuate edges alined for engagement with the respective bearers on the blanket cylinder, means for supporting the bearer members at such radial height on the impression cylinder that when the blanket cylinder rolls into the region of the gap on the impression cylinder upon reaching the end of the printing area the force of printing pressure between the cylinders is temporarily taken over by the auxiliary bearer members to achieve a smooth restoration of printing pressure upon reaching the end of the gap and at the beginning of the printing area thereby avoiding the cyclical impact accompanying sudden build-up of printing pressure, the impression cylinder including guiding means for guiding the bearer members in a generally radial direction along precisely parallel paths, and adjusting means for reproducibly adjusting the radial positions of the bearer members to precisely corresponding points along the parallel paths to preserve the smooth restoration of printing pressure upon making a change in the thickness of the sheet stock being printed.