Image reading device, adjustment method and non-transitory computer-readable recording medium encoded with adjustment program

A non-transitory computer-readable recording medium encoded with an adjustment program executed in a computer that controls an image reading device including a reading section having a plurality of optoelectronic transducers aligned in a main scanning direction,

• the adjustment program causing the computer to execute:
• a sub-scanning step of causing the reading section to scan a first sheet and a second sheet in a sub-scanning direction orthogonal to the main scanning direction, the first sheet and the second sheet respectively having a first edge and a second edge that intersect with each other and having a same size;
• and
• a determining step of determining an adjustment value that defines a length in the sub-scanning direction of image data output by the reading section based on first image data and second image data, the first image data being output by the reading section that scans the first sheet in a state in which an angle at which the first edge intersects with the main scanning direction is smaller than an angle at which the second edge intersects with the main scanning direction, the second image data being output by the reading section that scans the second sheet in a state in which an angle at which the second edge intersects with the main scanning direction is smaller than an angle at which the first edge intersects with the main scanning direction.