To surely perform a shading correction by differentiating a rotating direction of a belt-like white reference member from a feeding direction of a document, therby largely securing the data-obtainable portion of the white reference member.
While a white belt motor is controlled and a belt BX is being fed, dirt detection is performed upon the full length and the full width of the belt BX, and a situation of dirt is stored in a memory as data. When the dirt situation of the entire belt BX is recorded and confirmed, the belt BX is further fed in such a way that a dirty portion can not turned toward a side on which white detection is performed, and processing is finished. In a case where, e.g., dirt d1, d2, d3 is detected as a dirty state of the belt BX, positions of the dirt d1-d3 are determined, and the belt BX is fed for a suitable amount calculated from the positions, so that the portions of the dirt d1-d3 do not become the side of shading. A series of such work is implemented while document reading is not performed.
SANO MOTOYA
FUJII TAKASHI
KUBO HIROSHI
KITAOKA SHINYA
AKAI TAKESHI
MATSUSHITA SHINGO
KIMURA NORIO
MORITA KENICHIRO
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