A method includes separately conveying a first liquid solution containing the first material and a second liquid solution containing a liquid polyelectrolyte. Upon failure of the landline connection, an enterprise router switches over to a backup wireless packet-data link, such as a 3G cellular link for instance. A correction optical system provided between the semi-transmissive reflecting member and the reflecting member constituted of the concave mirror corrects an offset of the direction along which the light flux for focal point detection advances caused by the reflecting member constituted of the concave mirror, in conformance to the image height at the focal point detection position.