Image reading device determining whether dark output data is within prescribed range

An image reading device comprising:

• a reading unit configured to output image data by reading an original document, the reading unit having a light source and a light receiving unit, the light source being configured to emit light, the light receiving unit being configured to receive light;
• a command receiving unit configured to receive an instruction to control the reading unit to read the original document;
• a storing device storing reference dark output data and reference correction data assigned with the reference dark output data, the reference dark output data being generated based on read dark data outputted from the light receiving unit while the light source does not emit light;
• and
• a control device, after the command receiving unit receives the instruction, configured to:
• generate dark output data based on read data outputted from the light receiving unit while the light source does not emit light;
• determine whether the dark output data is within a first prescribed range into which the reference dark output data falls;
• select the reference correction data as selected correction data, when determining that the dark output data is within the first prescribed range;
• generate correction data to correct the image data when determining that the dark output data is not within the first prescribed range, and select, in place of the reference correction data, the generated correction data as the selected correction data;
• generate the image data by using the reading unit;
• and
• correct the image data by using the selected correction data.