Method of making transfer apparatus having vacuum holes

摘要

A transfer apparatus includes a transfer member, for example, a transfer drum with a line of small closely spaced laser drilled vacuum holes to hold a receiving sheet to the drum surface. The transfer drum is formed by forming a layer of at least intermediate conductivity material on the surface of a core, forming at least one vacuum opening in the core and laser drilling in the layer a line of closely spaced small holes communicating with the opening. In one embodiment, a short focal length lens focuses a laser beam near the surface of the layer, which beam spreads below the surface to form a conical hole. The conical hole helps maintain the continuity of a transfer field while being free from clogging.