Patent ID: 8649071

Claim:
An image reading apparatus comprising: an LED (Light emitting diode) for illuminating a document; a light guiding body disposed along a main scanning direction, the light guiding body including an incident surface formed on a first end side and arranged to face the LED, an emission surface formed on a document side to extend in the main scanning direction, a plurality of prisms for diffusing light that is aligned in the main scanning direction on a side facing the emission surface of the light guiding body, the plurality of prisms including at least one first prism that is disposed on an incident surface side in the main scanning direction, in which an angle of a prism incident plane with respect to the main scanning direction is greater than an angle of a prism anti-incident plane with respect to the main scanning direction, and at least one second prism that is disposed on an opposite end side to the incident surface side in the main scanning direction, in which an angle of a prism incident plane with respect to the main scanning direction is smaller than an angle of a prism anti-incident plane with respect to the main scanning direction, the light guiding body guiding light, which is emitted by the LED and incident upon the incident surface, in the main scanning direction and emitting the light from the emission surface; and a photoelectric conversion element that reads an image of a document by converting the light emitted from the emission surface of the light guiding body and reflected by the document to an electric signal.