Patent ID: 8405696

Claim:
A printing sheet reusability determination device comprising: an image erasing unit that erases an erasable image which is printed on a sheet using an erasable color material; a sheet carrying path that carries a first state sheet on which the erasable image is printed and a second state sheet passed through the image erasing unit; an imaging portion that images the second state sheet on the sheet carrying path; an illumination portion that illuminates the second state sheet on the sheet carrying path at a first irradiation angle when images remaining on the second state sheet are photographed, and at a second irradiation angle smaller than the first irradiation angle when a projected image generated by illuminating the second state sheet is photographed; an irradiation angle changing portion that changes the first irradiation angle and the second irradiation angle; and a reusability determination portion that determines whether or not to reuse the second state sheet based on imaging information obtained by the imaging of the imaging portion at the first irradiation angle and determines whether or not to reuse the second state sheet based on imaging information obtained by the imaging of the imaging portion at the second irradiation angle.