A cylinder is arranged to receive one or more hollow cylinders on an outer surface of the cylinder. The cylinder has at least one movable stop with at least one movable element. In an idle position the at least one movable element does not protrude beyond the outer surface of the cylinder and allows hollow cylinders to be slid over the cylinder, and in an active position it protrudes beyond the outer surface of the cylinder and acts as a mechanical stop for hollow cylinders. The at least one movable element can be moved from the idle position to the active position, and vice versa, by means of a rotary movement. A method for positioning a hollow cylinder on a cylinder of this kind.

A cylinder is arranged to receive one or more hollow cylinders on an outer surface of the cylinder. The cylinder has at least one movable stop with at least one movable element. In an idle position the at least one movable element does not protrude beyond the outer surface of the cylinder and allows hollow cylinders to be slid over the cylinder, and in an active position it protrudes beyond the outer surface of the cylinder and acts as a mechanical stop for hollow cylinders. The at least one movable element can be moved from the idle position to the active position, and vice versa, by means of a rotary movement. A method for positioning a hollow cylinder on a cylinder of this kind.

An apparatus for replacing printing sleeves comprising a handling device which can be removably engaged with a printing sleeve and a movement robot for moving the handling device; the handling device comprises a supporting frame, which is connected to the movement robot and supports a supporting rod which protrudes in a cantilevered manner from the supporting frame, and a grip assembly which is able to translate on command, with respect to the supporting frame, along a movement direction that is substantially parallel to the axis of the supporting rod, between an advanced working position and a retracted working position; the grip assembly is actuatable in rotation about an axis that is substantially parallel to the axis of the supporting rod.

An apparatus for replacing printing sleeves which comprises a handling device which can be removably engaged with a printing sleeve and a movement robot for moving the handling device; the handling device comprises a supporting frame and a self-centering grip clamp which is able to translate on command, with respect to the supporting frame, along a movement direction that is substantially parallel to the axis of the supporting rod, between an advanced working position and a retracted working position; the grip clamp has engagement elements which are movable on command between an inactive position and an active position, in which they are radially spaced apart from the axis of the supporting rod, in order to allow their engagement with the internal surface of the printing sleeve.

A printing plate unit to be demountably mounted on a printing plate mounting portion of a plate cylinder includes a printing plate and a printing plate coupling member. A length of the printing plate coupling member is larger than a width of the printing plate so that the printing plate coupling member is provided with a projecting portion projecting from the printing plate formed cylindrically in an axial direction. The printing plate unit is fitted to the printing plate mounting portion from one end side, and is demounted from the same one end side by gripping the projecting portion of the printing plate coupling member in a state both end portions of the printing plate formed into a cylindrical shape are coupled to each other by the printing plate coupling member.

An apparatus for replacing printing sleeves which comprises a handling device which can be removably engaged with a printing sleeve and a movement robot for moving the handling device; the handling device comprises a supporting frame and a self-centering grip clamp which is able to translate on command, with respect to the supporting frame, along a movement direction that is substantially parallel to the axis of the supporting rod, between an advanced working position and a retracted working position; the grip clamp has engagement elements which are movable on command between an inactive position and an active position, in which they are radially spaced apart from the axis of the supporting rod, in order to allow their engagement with the internal surface of the printing sleeve.