A flexographic printing unit is provided for a sheet along a printing line, including a plurality of printing assemblies, each including a printing roller apt to include a printing block, automatic and programmable movement apparatus for the printing rollers, apt to distance at least one of the printing rollers from the printing line during the printing procedure, so that the printing roller does not print the sheet, wherein each of the printing assemblies includes a structure fixed to the floor, at least one frame, which is movable with respect to the structure fixed to the floor, including at least one printing roller and apt to be moved by the displacement apparatus and damping apparatus arranged between the frame and a fixed point so as to damp the movement of the frame.

A liquid discharge head includes: a support member including a first recess and a second recess; and a damper member bonded to the support member, the damper member including a damper membrane, wherein the first recess faces the damper membrane, and the second recess is closer to an end of the support member than the first recess in a longitudinal direction of the support member, and the second recess does not face the damper membrane.

A drum support assembly (30, 32) for a printing machine is presented. It comprises a drum support body (30a, 32a) having a bearing interface (30b, 32b) for a drum, a lower guide (34) supporting the drum support body (30a, 32a) at a lower end thereof, and an upper guide (36) supporting the drum support body (30a, 32a) at an upper end thereof. Additionally, a pre-tensioning unit (50) is provided pre-tensioning the drum support body (30a, 32a) against the lower guide (34) and/or the upper guide (36). Furthermore, a printing machine is described, comprising a drum and a drum support assembly (30, 32) as described above.

A flexographic printing unit is provided for a sheet along a printing line, including a plurality of printing assemblies, each including a printing roller apt to include a printing block, automatic and programmable movement apparatus for the printing rollers, apt to distance at least one of the printing rollers from the printing line during the printing procedure, so that the printing roller does not print the sheet, wherein each of the printing assemblies includes a structure fixed to the floor, at least one frame, which is movable with respect to the structure fixed to the floor, including at least one printing roller and apt to be moved by the displacement apparatus and damping apparatus arranged between the frame and a fixed point so as to damp the movement of the frame.

A drum support assembly (30, 32) for a printing machine is presented. It comprises a drum support body (30a, 32a) having a bearing interface (30b, 32b) for a drum, a lower guide (34) supporting the drum support body (30a, 32a) at a lower end thereof, and an upper guide (36) supporting the drum support body (30a, 32a) at an upper end thereof. Additionally, a pre-tensioning unit (50) is provided pre-tensioning the drum support body (30a, 32a) against the lower guide (34) and/or the upper guide (36). Furthermore, a printing machine is described, comprising a drum and a drum support assembly (30, 32) as described above.

In a method to damp an oscillation of a roller driven via a drive in a printing system, a printing substrate web is directed across the roller, the roller and the printing substrate web forming a system capable of vibrating. With the drive the roller is driven with a predetermined nominal moment. With a sensor, a real value is determined of a variable representative of a velocity with which the printing substrate web is transported by the roller. In aid of a predetermined calculation rule, a correction moment is calculated from the determined real value such that a damping of the vibration-capable system results like a mechanical viscous damper. The correction moment is added to the predetermined nominal moment upon activation of the drive.