| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus and an image forming apparatus capable of accurately detecting size of a document without being adversely affected by a type and thickness of the document. <P>SOLUTION: In a document reading device reading a document by conveying it, a conveying amount of a document is detected after the document is detected by a sensor for detecting a position of a document, and reading data from a line sensor is stored in a memory, which is read by changing a lighting condition of a light source between a case where a document is conveyed in a conveyance direction and a case where the document is conveyed in the opposite direction of the conveyance direction. Then, a width of the document is calculated from the reading data based on the conveyance direction and the lighting condition of the illumination of the line sensor. <P>COPYRIGHT: (C)2012,JPO&INPIT |
