Abstract: An optical character reader apparatus includes an image sensor, and a background reflection plate having such reflectivity which allows the image sensor to detect the entry of a document carrying thereon image information such as characters, graphics or the like within the field of view of the image sensor.

Abstract: A switching power source device, in which a DC voltage obtained by rectifying an AC voltage is converted by switching elements into an AC voltage, which is subjected to voltage conversion by a transformer and rectified by a rectifier circuit to output a DC voltage therefrom. In one embodiment, a resonance capacitor and a saturable transformer form a series resonant circuit, and switching elements are subjected to frequency modulation control. In another embodiment, an inductor connected in parallel with a non-saturable transformer, and a capacitor connected in series to the same transformer, form a series resonant circuit, and the switching elements are subjected to frequency modulation control. In each embodiment, the series resonant circuit is subjected to frequency modulation control, and the electric currents from the switching elements do not rise and fall suddenly. Accordingly, switching losses and noise can be minimized, and the output voltages can be controlled easily.