IMAGE PROCESSOR

PROBLEM TO BE SOLVED: To avoid abnormal processing (interruption of read operation) due to staining of a small white reference plate which is not an impediment to document reading through a white reference platelet check system which can make a lamp check independently from shading operation (reference white plate read). SOLUTION: When a lamp 261 is turned on and the read operation is started, the white reference platelet 265 provided at a side part of a read slit (window) glass 264 is read to detect the white peak value of a sensor output, when the detection result deviates from a previously set normal value, another place of the white reference platelet 265 is read and when a detected white peak value deviates the normal value again, it is decided through the checks of the two places that the abnormality is caused not by accidental staining, etc., of the white reference platelet 265, but finally by the quantity of lamp light, etc. Then the started read operation is quit to perform no abnormal read output and the abnormality occurrence is indicated. When a peak value reaches the normal value in rechecking, shading or document read operation is carried out. COPYRIGHT: (C)2004,JPO