Toner amount measuring apparatus and method, and image forming apparatus using the same

摘要

A toner amount measuring apparatus includes an irradiating unit which divides a flux of laser beams emitted from a laser diode into two fluxes of laser beams by an obtuse-angled prism and makes the two light fluxes interfere with each other to form interference fringes on a photosensitive roll, and a photodetecting unit including an optical sensor for detecting reflection light obtained by reflecting the light constituting the interference fringes from the photosensitive roll.