| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a document scanner and image forming apparatus capable of reducing erroneous detection and detecting whether or not dust or the like is present on a scanning plane, with less memory and short-time control. Ž<P>SOLUTION: A document scanner and image forming apparatus includes: a mechanism for automatically feeding a document in a sub-scanning direction; a light source for irradiating a surface of the document; an optical system for guiding reflection light from the document to a predetermined position; a photoelectric conversion member placed at the predetermined position for performing photoelectric conversion on the reflection light; an A/D converter for performing analog-to-digital conversion on an image read value on which photoelectric conversion has been performed by the photoelectric conversion member; a comparison means for comparing scan data of a pixel and peripheral main scan pixels of that pixel with scan data digital-converted by the A/D converter lower than or equal to a predetermined value to background scan data; a detection means for detecting data wherein that pixel and the peripheral pixels have the same value and are continued in the sub-scanning direction and the number of lines of the continued pixels is equal to or more than the predetermined number of lines; and a replacement means for replacing the data detected by the detection means with the background scan data. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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