Patent ID: 8724128

Claim:
An image forming apparatus comprising: a light source which generates light used for reading an image; a light guide prism which extends in a main scanning direction and guides the light from the light source toward an image reading region; a holding unit which is connected to a part of the light guide prism to hold the light guide prism, has a wall surface distant from a first end surface of the light guide prism in the main scanning direction and facing a second end surface of the light guide prism, and has a linear expansion coefficient smaller than that of the light guide prism, wherein a clearance space is formed between the second end surface of the light guide prism and the wall surface in the main scanning direction; an image sensor which photoelectrically converts reflected light from the image reading region and outputs image data corresponding to the read image; and an image forming unit which forms an image on a sheet based on the image data of the image sensor.