There is disclosed a method and apparatus for transmitting a message to at least one group of users selected from a population of the users. The extruded image receiving layer is non-crosslinked and has a glass transition temperature of from about 40\xb0 C. The support platen has a predetermined thickness, a plurality of apertures through the thickness and a plurality of openings in a top surface in fluid communication with a gas source through the plurality of apertures. The present invention has small thickness, simple structure and low manufacturing cost. The bobbin body includes a coil termination block protruding radially from an inner flange of the two and having terminal pins for external connection, and the bobbin cover includes a termination protector protruding radially from the bobbin cover and adapted to mate with the coil termination block when the bobbin cover is put over the bobbin body.