A combustion system for performing stable combustion and flame stabilization at high altitudes is described. In accordance with the disclosure, a UE will generally transmit such measurement reports on subcarriers having particular subcarrier spacing. Elastically stretchable and contractable cover sheets are bonded to an upper surface of the napkin body. Since a just enough transfer current can be optimally generated, image quality can be improved and an image forming apparatus which does not need a large-capacity power source and an elastic roller are provided.