A printer includes a conveying unit for conveying a rewritable printing medium toward a discharging portion along a conveying path, and the rewritable printing medium is erasable and printable by applying heat energy to the rewritable printing medium. The steel sheet may include between about 0. A spreader plate of the heat spreader is in thermal contact with a microprocessor chip to be cooled and a plurality of spreader fins extending from the spreader plate.