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.