A high performance diplexer is disclosed having a common conductor which branches into two resonators in distributive form. With such diaphragm layer in the display apparatus, the brightness of the display apparatus can be enhanced by the Fresnel diffraction effects of the diaphragm layer. At gradually increasing spaces at the entrance end and the exit end of each nip portion of the image transfer carrying means, even with high transfer bias voltage, the discharge phenomenon and an undesired phenomenon of toner image scattering from predetermined positions are prevented, thus preventing the deterioration of image quality. The processor generates conceptual models and realization models in accordance with the meta-model profile. The second unit supports the motor and is slidable relative to the first unit.