1. An image processing device comprising: a segment extracting section that extracts, from a document image, a segment that is an image region containing a series of text characters of a uniform size; a segment designating section that, when the segment extracting section extracts a plurality of segments, designates one or more of the extracted segments each as an enlargement segment according to text sizes of the respective extracted segments; a scaling-factor determining section that determines a scaling factor for each of the one or more enlargement segments based on the text size of the enlargement segment and a standard text size; and an image creating section that enlarges each of the one or more enlargement segments at the scaling factor determined for the enlargement segment and creates a page image including the one or more enlargement segments as enlarged and one or more non-enlargement segments that are each undesignated segment among the extracted segments.