IMAGE READING DEVICE AND IMAGE FORMING APPARATUS

摘要

An image processing portion determines that a black stripe is present when among a plurality of main scanning lines included in a back end side range from a last back end position of the reading image data in a sub-scanning direction to a predetermined position, a main scanning line in which a density value of a pixels in a predetermined position is higher than a first threshold density is present, sets, at a reference line, a main scanning line farthest from the last back end position among the main scanning lines in which the density value of the pixel in the predetermined position is higher than the first threshold density and replaces density values of all pixels included in a range from a position of the reference line in the sub-scanning direction to the last back end position with a density value corresponding to white.

主权项

1. An image reading device comprising:
an original document transport unit that transports an original document to a reading position in which the original document is read; an image reading portion that includes a light source which is arranged on a downstream side in an original document transport direction with respect to the reading position when the original document is read in the reading position, that applies light of the light source to the original document transported to the reading position and that photoelectrically converts light reflected off the original document to generate image data of the original document; and an image processing portion that performs image processing on reading image data which is the image data of the original document obtained through reading of the original document by the image reading portion, wherein the image processing portion determines that a black stripe that appears when a shadow produced on a side of a back end of the original document transported to the reading position is read by the image reading portion in the reading image data is present when among a plurality of main scanning lines included in a back end side range from a last back end position of the reading image data in a sub-scanning direction to a predetermined back end side position, a main scanning line in which a density value of a pixels in a predetermined position is higher than a first threshold density is present, and when the image processing portion determines that the black stripe is present in the reading image data, the image processing portion sets, at a reference line, a main scanning line farthest from the last back end position among the main scanning lines within the back end side range in which the density value of the pixel in the predetermined position is higher than the first threshold density, and performs black stripe removal processing which replaces density values of all pixels included in a range from a position of the reference line in the sub-scanning direction to the last back end position with a density value corresponding to white.