A media roll holder assembly a web-based printing system comprises a support for rotatably supporting the roll in an operative position, a holding element for rotatably holding the roll on the support, and a pivotable arm on which the holding element is provided. The pivotable arm is formed and positioned to position the holding element on the roll, such that a lifting force for lifting the roll from the support results in a holding force on the holding element in the first angular direction for holding the roll in the operative position on the support. The roll is then rotatably secured in its operative without excess angular forces acting on the roll. As the rotation of the roll is substantially unimpeded, the medium may be transported with great precision, resulting in high quality printing.

A winding machine (10) is disclosed comprising at least one reel holder (12) mounted on a supporting frame (11) and rotatable around its own axis (13), and a plurality of reels (1-4) mounted on the holder (12) and integrally rotatable therewith so that at least one first reel (1) is in at least one operative winding position of a bobbin (5). It is further described a respective method for the in-line winding of bobbins (5) of stretch film (6), comprising the steps of rotating a core (7) on a reel (1) in an operative winding position to wind the film (6) onto the core (7), positioning a contact roll (15a) in at least one proximal contacting position in which it contacts the winding bobbin (5) for facilitating the peripheral winding of the stretch film (6) on the core (7), bringing the reel (1) from the operative winding position of the bobbin (5) to an operative unloading position of the bobbin, positioning an accompanying roll (15b) in at least one proximal contacting position in which it contacts the bobbin (5) for facilitating the peripheral winding of the stretch film (6) on the bobbin (7), transversally cutting the stretch film (6) and unloading the bobbin (5). The movement of the contact roll (15a) and the accompanying roll (15b) is carried out by means of electric actuators (18a, 18b).

An accompanying squeezing unit in a machine for winding plastic film onto bobbins, in which at least two spindles are positioned on a rotating plate around a central shaft constrained to an upright of the machine, the group including an accompanying squeezing roll situated on a lever mechanism which is selectively actuated to rotate-oscillate by actuators in order to maintain the squeezing roll positioned on a film in the final winding onto a bobbin positioned on one of the spindles, the lever mechanism being activated when the plate carrying the spindles is rotated to discharge a finished bobbin. The lever mechanism in the group includes two first levers and two second levers articulated relative to each other.

A media roll holder assembly a web-based printing system comprises a support for rotatably supporting the roll in an operative position, a holding element for rotatably holding the roll on the support, and a pivotable arm on which the holding element is provided. The pivotable arm is formed and positioned to position the holding element on the roll, such that a lifting force for lifting the roll from the support results in a holding force on the holding element in the first angular direction for holding the roll in the operative position on the support. The roll is then rotatably secured in its operative without excess angular forces acting on the roll. As the rotation of the roll is substantially unimpeded, the medium may be transported with great precision, resulting in high quality printing.

A winding machine (10) is disclosed comprising at least one reel holder (12) mounted on a supporting frame (11) and N rotatable around its own axis (13), and a plurality of reels (1-4) mounted on the holder (12) and integrally rotatable therewith so that at least one first reel (1) is in at least one operative winding position of a bobbin (5). It is further described a respective method for the in-line winding of bobbins (5) of stretch film (6), comprising the steps of rotating a core (7) on a reel (1) in an operative winding position to wind the film (6) onto the core (7), positioning a contact roll (15a) in at least one proximal contacting position in which it contacts the winding bobbin (5) for facilitating the peripheral winding of the stretch film (6) on the core (7), bringing the reel (1) from the operative winding position of the bobbin (5) to an operative unloading position of the bobbin, positioning an accompanying roll (15b) in at least one proximal contacting position in which it contacts the bobbin (5) for facilitating the peripheral winding of the stretch film (6) on the bobbin (7), transversally cutting the stretch film (6) and unloading the bobbin (5). The movement of the contact roll (15a) and the accompanying roll (15b) is carried out by means of electric actuators (18a, 18b).