Patent ID: 7791772

Claim:
An image reading device which includes a light source and a pickup device which face each other with an original platen for holding an original interposed therebetween, receives light irradiated from the light source by the pickup device, and reads a light transmission original, the image reading device comprising: a pickup device movement mechanism which reciprocally moves the pickup device in a predetermined direction; a light source movement mechanism which reciprocally moves the light source in the predetermined direction in interlock with the reciprocal movement of the pickup device movement mechanism in a movement range which is set to be less than a movement distance of the pickup device; and a connection mechanism which has a torque limiter function for generating sliding between the light source movement mechanism and the pickup device movement mechanism when torque equal to or greater than a predetermined value is delivered, and interlockingly connects the light source movement mechanism to the pickup device movement mechanism.