Document image reading device

摘要

The invention is directed to provide a document-image reading device that can analyze a speed fluctuation state of a scanner when scanning an image in the feed direction by separately extracting speed fluctuation components by reading a change in density of reference scale lines and, on the basis of the analysis result, prevents the occurrence of an image blur that may be resulting from unstable factors of a driving mechanism. The document-image reading device for reading a document image data at a specified time-interval given by the reference clock signal, which comprises document-image reading means for reading a document image by moving the means or the document in the feed direction and is featured in that the document-image reading means is further provided with chart reading means for reading a reference chart portion having alternations of a high-density division and a low-density division arranged one after another at a distance-interval equal to a least pitch readable by the document-image reading means along the feed direction and processing means for processing image data read from the reference chart portion integration by using a comb-type filter and by integration.