In recent years, many CI Flexo Printing Machines have gradually adopted the cantilever type rewinding and unwinding structure, which is mainly characterized by fast reel change and relatively less labor. The core component of the cantilever mechanism is the inflatable mandrel. The driving side of the mandrel is fixed on the frame, and the operating side is suspended when changing the coil, which is convenient for installing and unloading the coil. It is then carried on foldable frame parts connected by door shafts. Compared with the core-through air-expansion shaft structure, the cantilever structure is easier to operate when changing rolls.