Disclosed is a reader-printer being capable of erasing a frame surrounding margin of a microfilm and unnecessary image portion in the frame. The reader-printer comprises first flap member, second flap member which are disposed adjacent to a slit and movable in and out of a light path directing toward a photosensitive drum and a lamp to illuminate those flap members when they are moved into the light path. The first flap member is movable in the longitudinal direction along the slit for varying a shading area.