Patent ID: 8837008

Claim:
An image reading apparatus comprising: a table having a surface on which an original is placed; a carriage that includes an image sensor mounted thereon and configured to move in a scan direction parallel to the surface and crossing a longitudinal direction of the image sensor; and a drive unit that is mounted on the carriage so as to move with the carriage in the scan direction, the drive unit including: a motor having a rotary shaft and a motor housing, a gear train configured to transmit rotation of the rotary shaft so as to move the carriage, a code wheel fixed to the rotary shaft, an encoder sensor including a sensor housing and a sensing element mounted in the sensor housing, the encoder sensor configured to read the code wheel, and a motor holder configured to hold the motor housing, the motor holder being fixed on the carriage, wherein the sensor housing comes into contact with the motor holder by being urged with a resilient member in a direction substantially parallel to an axis of the rotary shaft, such that both of the motor housing and the sensor housing are positioned with respect to the motor holder.