A pencil sharpener includes a base having a bottom surface adapted for being supported by a horizontal surface. In an embodiment, a power circuit, which may be a switched mode power circuit, is shut down during performance of the measurements to reduce interference. The control unit copes with the projectors depending upon the detection result received from the projectors, to set predetermined control data for use in image-quality adjustment and send the control data respectively to the projectors. Finally, the supply is authorized for use with the identification card manufacturing system only when the translated SSSC is found to be valid. The concentrate obtained is fully adapted for therapeutic use as substitution therapy in cases of Factor XI deficiency.