An image forming apparatus includes a pre-fixing sheet guide and a toner collection device. The apparatus comprises a suction conduit structure that includes a main conduit portion and a pair of secondary conduit portions extending from the main conduit portion. Each flange includes an integral leaf spring. The role of a photocatalyst is to produce highly reactive species or radicals and initiate the degradation of a stain upon exposure to elements, such as, sunlight, air and ambient humidity. The bit rate changeover switch selects an electric signal corresponding to the bit rate of the light signal so as to input it into a modulating electric signal generating unit. A dry cleaning process is performed on the wafer surface using a mixture of nitrogen and hydrogen as the reactive gases.