Patent ID: 8059315

Claim:
An image reading device comprising: a conveying means for conveying in a conveying direction a target to be light-irradiated including a transparent portion; a lens assembly, positioned on one side of the target, for focusing transmission light having passed through the transparent portion of the target; a sensor for receiving the transmission light focused by the lens assembly; a light guide, positioned on the other side of the target, extending in a main-scanning direction and a sub-scanning direction; an array light source, provided at an end portion of the light guide, in which light sources are arranged in an array along the main-scanning direction, for emitting light in the sub-scanning direction into the light guide; and a reflective portion, formed at a position where optical axes of the array light source intersect with the light guide, for reflecting light emitted from the array light source in the sub-scanning direction to a light irradiated portion where the target is irradiated with light, wherein the reflective portion tilts the light emitted from the array light source with respect to the optical axis of an imaging optical system as the lens assembly so as to irradiate the target.