Image reading apparatus and image forming apparatus incuding the same

• Main Authors: FUKUTOME SHOHICHI, NAKANISHI KENJI, IMOTO MASAHIRO, OGASAWARA HIRONORI, YOSHIMOTO MITSUHARU
• Format: Patent
• Language: Chinese; English
• Published: 24.09.2014
• Subjects: CINEMATOGRAPHY; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; HOLOGRAPHY; MAGNETOGRAPHY; PHOTOGRAPHY; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION

An image reading apparatus of the present invention includes a photoelectric transducer that performs reading scanning along a main scanning line and reads an original, the image reading apparatus obtaining a white shading level of pixels based on an output level of the photoelectric transducer obtained when a reference white is read, obtaining a black shading level of the pixels based on an output level of the photoelectric transducer obtained when a black reference is read or obtained in a dark condition, and correcting the output level of the photoelectric transducer obtained when an original image is read with the use of the white shading level and the black shading level, and the image reading apparatus further comprising a correction unit that obtains a variation amount of the white shading level between a pixel and other pixels in the vicinity of that pixel for each of pixels on the main scanning line, determines whether the variation amount exceeds a pre-set threshold value, and when the correction un