Image reading apparatus provided with guide rail to guide image reading unit to read document and fix the guide rail with an adhesive

An image reading apparatus, comprising:

• a guide rail extending in a longitudinal direction;
• an image reading unit configured to read an image, the image reading unit including a slider that is configured to slide along the guide rail in a state where the slider contacts the guide rail, the slider sliding along the guide rail when the image reading unit is guided by the guide rail and moved in the longitudinal direction;
• a first portion configured to abut on the guide rail so as to determine a position of the guide rail in a lateral direction, substantially perpendicular to the longitudinal direction, and in a vertical direction, substantially perpendicular to both the longitudinal direction and the lateral direction;
• a second portion configured to abut on the guide rail so as to determine the position of the guide rail in the lateral direction and in the vertical direction, wherein the second portion is provided at a different position from the first portion in the longitudinal direction;
• a third portion provided between the first portion and the second portion in the longitudinal direction, the third portion extending in the longitudinal direction and having a gap with the guide rail;
• and
• an adhesive applied to the gap, the adhesive contacting the guide rail and the third portion so as to fix the guide rail to the third portion in the longitudinal direction, in the lateral direction, and in the vertical direction,
• wherein a length of the third portion in the longitudinal direction is longer than a length of the first portion in the longitudinal direction and is longer than a length of the second portion in the longitudinal direction.