A method for predicting when maintenance is required for a scanner comprises tracking a quality parameter history in a scanner, predicting when maintenance is required based on the quality parameter history, and notifying a user when maintenance is predicted to be required based on a quality parameter trend. In the rack structure of the communication apparatus, the air used for cooling printed circuit boards within a lower shelf and thereby increased in temperature is cooled by causing the same to flow through the heat-dissipating duct on a lateral side and is then used again for cooling printed circuit boards within an upper shelf. The tapered tube is used as a substrate from which a laser cuts interconnecting stent struts. The mount has spring elements which are constructed monolithically with the bearing elements and are soft in axial and radial directions. The textures include high frequency components superimposed on the low frequency components. The thin film photoelectric conversion module includes a substrate and a plurality of photoelectric conversion cells formed on the substrate and connected to each other in series to form a series-connected array.