Preventing component collision in image reading apparatus during change of state

An image reading apparatus comprising:

• a first unit including a first image sensor configured to read a first side of a document;
• and
• a second unit configured to be opened or closed with respect to the first unit, the second unit including a second image sensor configured to read a second side opposite to the first side of the document, wherein
• the first unit includes a first background plate configured to be switched between a facing state in which the first background plate faces the second image sensor and a non-facing state in which the facing state of the first background plate and the second image sensor is released,
• the second unit includes a second background plate configured to be switched between a facing state in which the second background plate faces the first image sensor and a non-facing state in which the facing state of the second background plate and the first image sensor is released, and a power receiving section configured to receive power from a motor to switch the state of the second background plate,
• the first unit includes
• the motor;
• an intermediate cam configured to be rotated by the power from the motor;
• a holding member configured to hold the intermediate cam in a neutral position in a state in which the power of the motor is not transmitted to the intermediate cam;
• and
• a cam member configured to receive the power of the motor via the intermediate cam, the cam member having a receiving section of a size the power receiving section is received regardless of a position of the power receiving section when the intermediate cam is in the neutral position, the cam member configured to move the power receiving section by rotation.