Patent ID: 8253987

Claim:
An image reader, comprising an all-in-one optical scanning unit that moves in a sub-scanning direction orthogonal to a main scanning direction to read an original image on an original document sheet, the optical scanning unit comprising: a housing that houses a reading device to read light reflected by the original document sheet; a lighting device detachably attached to the housing to emit light toward the original document sheet; a shield member detachably attached to the housing to shield the reading device from the lighting device to form a space for the reading device inside the housing; a slit provided in the shield member and extending in the main scanning direction to guide the light reflected by the original document sheet to the space for the reading device; a first positioner provided in the housing; and a second positioner provided on the shield member to engage the first positioner provided in the housing to position the reading device with respect to the lighting device, the lighting device comprising: a light source to emit light; and a reflection member integrally provided on the shield member to reflect the light emitted by the light source toward an irradiation region on the original document sheet.