Abstract: An article detection device includes: a light emission unit for emitting a detection light for irradiation onto an article, and a light reception unit for receiving a light reflected from the article. The article detection device also includes; an analog-to-digital converter for converting the reflected light to a digital signal, a first register for storing the digital signal after being sampled using a first sampling signal having a first period, and a second register for storing the digital signal after being sampled using a second sampling signal having a second period shorter than the first period.

Abstract: An optical scanner is disclosed wherein coded bars are scanned by a laser beam to effect reading of a bar code of the coded bars. The optical scanner includes a rotary polygon mirror having a plurality of reflecting portions provided thereon around an axis of rotation thereof for reflecting a laser beam from a light source toward coded bars. Each reflecting portion of the rotary polygon mirror has a plurality of reflecting faces having different inclination angles from each other with respect to the axis of rotation such that an inclination angle of a line of intersection between adjacent reflecting faces of each reflecting portion with respect to the axis of rotation is different from an inclination angle of a line of intersection between adjacent reflecting faces of each of adjacent ones of the reflecting portions on the opposite sides of the reflecting portion with respect to the axis of rotation.