Patent ID: 6870558

Claim:
An illuminance correcting method for an optical fixing unit including a luminous-element array being as a light source in which luminous elements for radiating ultraviolet rays are arranged in matrix so as to align in a scanning direction and a feeding direction, said optical fixing unit performing optical fixation by the ultraviolet rays of said light source during conveyance of a thermosensitive recording material for which thermal recording is already carried out, and said optical fixing unit being used in a thermal printer thermally recording an image by heating the thermosensitive recording material conveyed in the feeding direction with a thermal head disposed in the scanning direction, said illuminance correcting method comprising the steps of: obtaining integral illuminance of the luminous elements belonging to each line extending in the feeding direction of said luminous-element array; checking illuminance distribution in the scanning direction on the basis of the obtained integral illuminance; and correcting the integral illuminance with respect to the respective lines so as to even out the illuminance distribution in the scanning direction.