An optical scanning device includes a deflector including a first deflection surface configured to deflect first and second light beams to scan first and second scanned surfaces in a main scanning direction, respectively, and first and second optical systems configured to guide the first and second light beams deflected by the first deflection surface to the first and second scanned surfaces, wherein the first and second optical systems include a common first optical element disposed on first and second optical paths, wherein the first optical system includes a second optical element located between the first optical element and the first scanned surface, wherein the second optical system includes a third optical element located between the first optical element and the second scanned surface, and wherein the first optical element includes first and second optical portions on which the first and second light beams are incident.

An image reading device includes a board including a plurality of imaging elements arranged along a scanning direction, and a housing including a plurality of optical components that are arranged along the scanning direction and a plurality of housing components that are arranged along the scanning direction. Each of the plurality of optical components focuses light reflected by a reading target onto a corresponding imaging element, and each of the plurality of housing components holds at least one optical component. The plurality of housing components are arranged to have a clearance therebetween and each of the plurality of housing components is fixed to the board at a position to transmit light through the optical components to focus onto the corresponding imaging element.

A skew adjustment mechanism for a scanning device includes a frame rack, an image sensor, a support frame, and a bearing base. The frame rack includes elastic elements on its bottom side and a guide slot positioned on its inner side edge. The image sensor, disposed on the frame rack, includes friction parts on two sides. The elastic elements abut against the two sides of the image sensor. The support frame, positioned below the frame rack, includes a fixing plane with a through hole for accommodating a penetrating element. The bearing base, cooperating with a guide rod to slide, supports the support frame and the frame rack. The penetrating element extends through the through hole into the guide slot and is fixed inside the frame rack. A skew angle of the image sensor is adjustable by changing a position of the penetrating element within the guide slot.

An optical line sensor reads an inspection object conveyed in a sub-scanning direction by a reading line L extending in a main scanning direction and includes a plurality of light-receiving lenses 11 and a plurality of light-receiving elements. The plurality of light-receiving lenses 11 are arranged along the main scanning direction. The plurality of light-receiving elements are arranged linearly along the main scanning direction, and receive light transmitted through the plurality of light-receiving lenses 11. The plurality of light-receiving lenses 11 are arranged to be separated from each other by a diameter of the light-receiving lens 11 or longer. A plurality of light-receiving elements 121 form at least one row or more of the reading lines L.