Image reading apparatus, image forming apparatus, and reading control method

A reading control method for an image reading apparatus including:

• a light source that emits light;
• a reference sheet that reflects the light emitted from the light source;
• a light-receiving lens that converges the light reflected from the reference sheet;
• and a reading sensor that reads the light converged by the light-receiving lens, the method comprising:
• based on first white data obtained when the reading sensor reads the reference sheet for the first time, determining whether the reference sheet or the reading sensor has dust;
• in response to determining that the reference sheet or the reading sensor has dust, producing ideal initial white reference data by complementing the first white data with second white data obtained when the reading sensor reads the reference sheet for the second and subsequent times;
• and
• with the ideal initial white reference data, complementing third white data obtained when the reading sensor reads the reference sheet right before reading an image of a job.