Provided is a scanner having sixteen or fewer sensor chips capable of scanning an A4 document; an optical unit that reduces and focuses an image of an A4 document on the sensor chips; and a generator that synthesizes images of the A4 document read by the sensor chips, and generates image data.

According to one embodiment, an image reading apparatus includes: a first illumination device for irradiating light at a first angle onto a sheet that is being conveyed; a second illumination device for irradiating light at a second angle onto the sheet that is being conveyed; illumination controllers for switching between a first irradiation state in which light is irradiated from the first illumination unit and the second illumination unit onto the sheet and a second irradiation state in which light is irradiated from only either the first illumination device or the second illumination device to the sheet; an imaging device for acquiring a first comparable image in the first irradiation state and for acquiring a second comparable image in the second irradiation state; and a defect detector for detecting a defect of the sheet based on the difference between the first comparable image and the second comparable image.

An image scanner, which is incorporated in an image forming apparatus, includes a stationary-document reading section, a moving-document reading section disposed at an angle to the stationary-document reading section, a reader movable between the stationary-document reading section and the moving-document reading section, and a reading element movable to different angles while contacting the stationary-document reading section and the moving-document reading section to selectively read a document placed on the stationary-document reading section and a document moving over the moving-document reading section. The image scanner further includes any one of position detector, a combination of a moving device and at least one position sensor, and a combination of at least one pressing member, a framework, and an angle changer.