The invention relates to a method and a heating device for heating at least one printing agent on a printing material (4), which is passed along a transport path through said heating device, comprising at least one microwave applicator (2) and at least one microwave absorber element in the outer perimeter of said microwave applicator. The object of the present invention is to reduce the loss of energy due to microwave radiation exiting from the microwave applicator (5). The object of the invention is achieved in that the minimum of one microwave absorber element is an irradiation device that absorbs microwave radiation and emits electromagnetic radiation, in which case said irradiation device, in accordance with the method herein, is energized by microwave radiation, applies radiation to the printing agent and/or the printing material (4), and thus at least aids the heating process.