PURPOSE: To restrain static electricity from being generated between paper and an apron by a method wherein a frictional coefficient of a surface of the apron is decreased during operation of a paper moving type plotter.

CONSTITUTION: An anodic oxidation film 14 is formed by an anodic oxida tion treatment on a surface of an apron body 13' formed of aluminum or aluminum alloy. Further, molybdenum disulfide layer 15 is laminated by electrodeposition on its surface and besides, holes 16 formed in the anodic oxidation film 14 are filled with molybdenum disulfide 15'. Since the holes formed in the anodic oxidation film are filled with molybdenunm disulfide connected to the molybdenum disulfide layer thereby, the molydenum disulfide layer is difficult to peel off from the anodic oxidation film. Therefore, effect for restraining static electricity on the surface of the apron is kept for a long time.