A roller for a printing unit of a printing press, has a roller outer body, which is mounted on a roller inner body, so as to be movable axially in a reciprocating manner. For the axial movement of the roller outer body, in at least a first direction, a pneumatic drive is provided. The pneumatic drive has at least one first chamber, which is mounted in the interior of the roller in the manner of a cylinder/piston system between one or more structural elements, that are fixed to the roller outer body, and one or more structural elements that are fixed to the roller inner body. The chamber can be pressurized with compressed air. The parts of the structural elements adjoining the chamber, and that are movable axially relative to one another, form a non-contact seal between themselves on their mutually facing sides.

A ductor roll assembly for use in an ink station assembly of a can decorator for communicating ink from a fountain roll to a distributor roll. The ductor roll assembly having a roll portion including an elongated axial member and a plurality of segments selectively disposed on and around the axial member axially adjacent each other for rotation about a rotation axis. The plurality of segments includes: a number of ink transfer segments, each ink transfer segment having an ink transfer surface disposed at a first radial distance from the rotation axis and structured to transfer ink between a corresponding axial portion of a fountain roll and a corresponding axial portion of a distributor roll; and a number of spacer segments having a second outer diameter less than the first outer diameter.

A ductor roll assembly for use in an ink station assembly of a can decorator for communicating ink from a fountain roll to a distributor roll. The ductor roll assembly having a roll portion including an elongated axial member and a plurality of segments selectively disposed on and around the axial member axially adjacent each other for rotation about a rotation axis. The plurality of segments includes: a number of ink transfer segments, each ink transfer segment having an ink transfer surface disposed at a first radial distance from the rotation axis and structured to transfer ink between a corresponding axial portion of a fountain roll and a corresponding axial portion of a distributor roll; and a number of spacer segments having a second outer diameter less than the first outer diameter.

A ductor roller for printing machines has a shaft provided with an air supply pipe, plural individual ductor rollers, and plural electromagnetic valves, both connected to the shaft. The individual ductor rollers advance pneumatically by the electromagnetic valves. The individual ductor rollers have housings that are associated with the shaft and configured to move forward and backward; roller members configured to contact with the ink fountain roller and an ink distribution roller; and bearings connecting the roller members to the housings. The electromagnetic valves are placed in the housings. Protection members for the electromagnetic valves are oil-resistant, have circularly cylindrical or arc-like covers, and are associated with the shaft. They cover the side ends of the housings and are placed in the clearance between the individual ductor rollers. The protection members do not need an exchange, discharge cleaning liquid for printing machines along troughs and prevent the electromagnetic valves from being contaminated by the cleaning liquid.

An inking system for use in transferring ink to a flexographic printing plate in a flexographic printing system includes an anilox member having an ink transfer zone located between first and second recessed bearing contact zones. A radius of the recessed bearing contact zones is less than a radius of the ink transfer zone by at least 0.100 inches. An ink tray includes a floor and first and second end walls. Bearings are mounted outside of the end walls which engage with the first and second bearing contact zones, respectively, thereby positioning the ink tray assembly in a specified position relative to the anilox member. Upper edges of the end walls extend into the recessed bearing contact zones.

A roller for a printing unit of a printing press, has a roller outer body, which is mounted on a roller inner body, so as to be movable axially in a reciprocating manner. For the axial movement of the roller outer body, in at least a first direction, a pneumatic drive is provided. The pneumatic drive has at least one first chamber, which is mounted in the interior of the roller in the manner of a cylinder/piston system between one or more structural elements, that are fixed to the roller outer body, and one or more structural elements that are fixed to the roller inner body. The chamber can be pressurized with compressed air. The parts of the structural elements adjoining the chamber, and that are movable axially relative to one another, form a non-contact seal between themselves on their mutually facing sides.

A ductor roller for printing machines has a shaft provided with an air supply pipe, plural individual ductor rollers, and plural electromagnetic valves, both connected to the shaft. The individual ductor rollers advance pneumatically by the electromagnetic valves. The individual ductor rollers have housings that are associated with the shaft and configured to move forward and backward; roller members configured to contact with the ink fountain roller and an ink distribution roller; and bearings connecting the roller members to the housings. The electromagnetic valves are placed in the housings. Protection members for the electromagnetic valves are oil-resistant, have circularly cylindrical or arc-like covers, and are associated with the shaft. They cover the side ends of the housings and are placed in the clearance between the individual ductor rollers. The protection members do not need an exchange, discharge cleaning liquid for printing machines along troughs and prevent the electromagnetic valves from being contaminated by the cleaning liquid.

A printing machine has an ink fountain, a fountain roller in contact with the ink fountain, a ductor roller, at least an ink transfer roller and a controller configured and programmed to control the ductor roller. For the printing machine, individual graph data gr and its initial values gri, and average g of the graph data over the entire ductor roller and its initial value gi are used to change graph data gr and g during printing so as to cancel errors between measured printed densities and desired printed densities. An adjustment apparatus and method also achieve this task for such a printing machine.

An inking system for use in transferring ink to a flexographic printing plate in a flexographic printing system includes an anilox member having an ink transfer zone located between first and second recessed bearing contact zones. A radius of the recessed bearing contact zones is less than a radius of the ink transfer zone by at least 0.100 inches. An ink tray includes a floor and first and second end walls. Bearings are mounted outside of the end walls which engage with the first and second bearing contact zones, respectively, thereby positioning the ink tray assembly in a specified position relative to the anilox member. Upper edges of the end walls extend into the recessed bearing contact zones.

Provided is an ink supply device for a printer, which does not require cleaning process by manual work, even in the case where ink remains in gap portions between adjacent divided ink ductor rollers. A divided ink ductor roller cleaning unit 7 is provided, which includes a cleaning roller 21 having an outer periphery covered with a cleaning fabric 26 and having an axis parallel to an axis of a plurality of divided ink ductor rollers 4. The cleaning roller 21 is pressed against the plurality of divided ink ductor rollers 4, and the cleaning fabric 26 enters gap portions between the adjacent divided ink ductor rollers 4, whereby the divided ink ductor roller cleaning unit 7 wipes off ink adhering to outer peripheral portions of end faces of the divided ink ductor rollers 4.