Image-reading device comprising a plurality of optical components arranged along the scanning direction board components arranged to have a second clearance therebetween and board components fixed to the housing

An image reading device comprising:

• a board including a plurality of imaging elements arranged along a scanning direction and a plurality of board components arranged along the scanning direction, each of the plurality of board components being mounted with at least one imaging element included in the plurality of imaging elements;
• and
• a housing to hold a plurality of optical components arranged along the scanning direction, each of the plurality of optical components being configured to focus light reflected by a reading target onto a corresponding imaging element included in the plurality of imaging elements, wherein
• the plurality of board components are arranged to have a second clearance therebetween,
• each of the plurality of board components is fixed to the housing at a position to transmit light through the optical component to focus onto the corresponding imaging element,
• each of the plurality of board components has a surface facing the housing and is fixed to the housing at a region including a center of the surface, and
• the second clearance has a width in the scanning direction that is larger than or equal to a difference between a linear expansion of the housing and a linear expansion of each of the plurality of board components in the scanning direction.