Abstract: An arrangement for driving at least one roller of a roller unit for transporting web-shaped materials, such as X-ray sheet films or stimulatable phosphorous foils with substantially constant speed in a device for exposing or scanning these materials, the arrangement comprising a stepping motor having a motor output shaft, a friction drive having a drive input shaft, and a vibration damping mechanism provided between said motor output shaft and the drive input shaft. The drive is formed so that a ratio of the drive and a diameter of the roller is selected so that at least 20 steps of the stepping motor corresponds to a transporting path of the web-shaped material of one millimeter.