To provide good resolution on the order of 0.5 mm, for example, and to easily and accurately detect defective print on a printed material.
This device comprises a detector 11 and an image processor 15. The detector 11 is equipped with three light emitting diodes 39A, 39B, and 39C, disposed above a guide member 9 of a printer to irradiate the printed material with light of three colors, red, green, and blue, and a monochrome CCD camera 41 for detecting actual image data by receiving the quantity of reflected light reflected from the printed material 3 in the running direction. The image processor 15 is equipped with a reference image data memory 33 for storing reference image data which are image data of good paper previously detected/found, and a comparison/computation part 35 for comparing/computing the actual image data detected by the detector 11 with the reference data stored in the data memory 33.
SHOJI TAKAO
KAWAKUBO TAKASHI
