The invention relates to a device for comminuting particles in a liquid material, in particular a powder or a semi-liquid for producing a chocolate mass. As such, periodic performance of a non-user-initiated preventative maintenance mode based on the preventative maintenance mode parameters results in the ink within the inkjet-printing mechanism being sufficiently fresh so as not to affect quality of image formation by the inkjet-printing device. The curtain is wrapped around a spindle that is connected to a spool via two cords. The first cylinder head and the second cylinder head are associated with the engine. The switch nail is controlled so that a jammed paper is conveyed to the paper container via the branch conveying path upon detecting paper jamming in the paper conveying path and the first sensor detects the jammed paper while the second sensor does not detect the jammed paper.