CONTROLLED ASYNCHRONOUS-MOTOR DRIVE DESIGNED FOR A ROTATING-DRUM SCANNER AND WITH A HOLLOW-SHAFT ROTOR FOR THE INTERNAL ILLUMINATION DEVICE

摘要

Vertical rotating-drum scanners, with a fixed or replaceable drum fitted on one side, for scanning direct-view images or transparencies must not only ensure vibration-free rotation of the drum but must also have a very compact design. The invention meets both requirements by using a controlled, direct asynchronous drive which avoids jitter caused by transmission equipment such as gearing of any kind, the drive rotor being designed as a hollow shaft which is also the scanner-system axle. The hollow-shaft design enables the light for the internal illumination of the drum to be guided along the hollow shaft, thus saving space.