1. An image processing device comprising: a segment extracting section that has an optical character recognition function and that is configured to detect text characters from a document image using the optical character recognition function, extract a series of text characters of a uniform size that are adjacent to one another among the text characters detected using the optical character recognition function, extract a rectangle region circumscribing the extracted text characters as a segment, extract a plurality of the segments, the respective segments containing text characters different in size from one another; a segment designating section configured to designate a plurality of enlargement segments, cause the plurality of extracted segments to be displayed on a display device, set, when one of the plurality of extracted segments displayed on the display device is selected by the user, a text size of the text character contained in the segment selected by the user; and designates a plurality of segments each containing a text character having a text size equal to or smaller than the text size of the text character contained in the segment selected by the user among the plurality of extracted segments as the enlargement segments; a scaling-factor determining section that determines a scaling factor for each of the enlargement segments, the scaling factor being a value of a ratio between the text size of the text character contained in each of the enlargement segments and a standard text size; and an image creating section that equalizes the text sizes of the text characters contained in the enlargement segments by enlarging each of the enlargement segments at the scaling factor determined for the enlargement segment and creates a page image including the enlargement segments as enlarged and a plurality of non-enlargement segments other than the enlargement segments, wherein the standard text size is determined by the scaling-factor determining section as a smallest text size among text sizes of text characters contained in respective non-enlargement segments not selected by the user other than the enlargement segments, wherein the standard text size is larger than the text size of the text character contained in the segment selected by the user.