Apparatuses for producing optical effect layers

An apparatus for producing an optical effect layer, comprising:

• a holder, including surrounding sidewalls and an accommodating recess spatially defined by the surrounding sidewalls, along an axis the holder having mounted thereto in the accommodating recess:
• a motor;
• a permanent magnet assembly;
• and
• a support configured to be removably fixed to the holder, wherein the support accommodates the permanent magnet assembly,
• wherein the motor is configured to spin the permanent magnet assembly around the axis in the support, wherein the holder includes a bottom surface and a removable fixation on the bottom surface, the bottom surface is curved according to a curvature radius of a circumferential mounting groove of a rotating magnetic cylinder of a printing unit, and the removable fixation of the holder is configured to be removably fixed to the circumferential mounting groove of the rotating magnetic cylinder of the printing unit, wherein the axis is substantially perpendicular to the bottom surface of the holder;
• wherein the holder includes a lower recess between the accommodating recess and the bottom surface, at least a part of the motor is disposed in the lower recess of the holder, and the motor includes a central hole to provide access to the removable fixation:
• and
• wherein the permanent magnet assembly is removably fixed to the holder.