An image reading apparatus includes an image reading chip for reading an image. The image reading chip includes a plurality of pixel units which include a light receiving element which receives light from the image so as to perform photoelectric conversion, an analog circuit, a logic circuit, and a power source pad to which a power source voltage is supplied. The image reading chip has a shape which includes a first side and a second side shorter than the first side. A distance between the analog circuit and a median point of the first side is shorter than a distance between the logic circuit and the median point of the first side, and a distance between the analog circuit and the power source pad is shorter than a distance between the logic circuit and the power source pad.

In an image reading device, a controller is configured to perform: calculating a ratio between first and second reference data as evaluation data; designating a target light receiving element from a plurality of light receiving elements one by one sequentially; calculating average evaluation data of the target light receiving element by averaging the evaluation data of a second number of light receiving elements located at positions apart every predetermined distance equal to a length of a first number of consecutively arranged light receiving elements; setting an evaluation range of the target light receiving element by adding/subtracting a predetermined value to/from the average evaluation data; determining whether the evaluation data falls within the evaluation range; in response to determining that the evaluation data is out of the evaluation range, revising the second reference data of the target light receiving element; and generating correction data using the second reference data after revision.

An image reading apparatus includes a stacking unit, a conveyance unit to convey stacked sheets, a reading unit, a white reference plate provided in a second position, and a processor. The reading unit is movable and, at a first position, reads a conveyed sheet image to obtain image data and, at the second position, reads the white reference plate. The processor generates, based on a plate reading result, a shading correction value and corrects the image data using the shading correction value. Based on whether the number of times in which reading the white reference plate has been performed is less than a predetermined number of times, the reading unit changes a time interval in a reading period that is from a first timing to a second timing. The processor generates, each time the white reference plate is read, the shading correction value based on the plate reading results.

An image reading apparatus includes a stacking unit, a conveyance unit to convey stacked sheets, a reading unit, a white reference plate provided in a second position, and a processor. The reading unit is movable and, at a first position, reads a conveyed sheet image to obtain image data and, at the second position, reads the white reference plate. The processor generates, based on a plate reading result, a shading correction value and corrects the image data using the shading correction value. Based on whether the number of times in which reading the white reference plate has been performed is less than a predetermined number of times, the reading unit changes a time interval in a reading period that is from a first timing to a second timing. The processor generates, each time the white reference plate is read, the shading correction value based on the plate reading results.

A position of a first registration mark printed on a substrate during an earlier printing operation is detected. A second registration mark is printed on the substrate during a current printing operation at a position on the substrate relative to the first registration mark based on the detected position of the first registration mark and a correction factor. An alignment difference between the position of the first registration mark and the position of the second registration mark is measured. A new correction factor for a subsequent printing operation is calculated by weighting the measured alignment difference according to a difference between the measured alignment difference and a previous measured alignment difference.

An image scanning apparatus, comprising: a scanning device; a reference member; a correction unit; a controller; and a storage device, the scanning device comprising light receiving elements and a lens array, wherein the controller executes: a preparation process and an executive process, the preparation process comprising: a white reference data obtaining process to obtain white reference data by scanning a white reference original; and a white storing process to obtain white basic data by averaging the white reference data of a particular number of adjoining light receiving elements, wherein the executive process comprises: a reference member data obtaining process to obtain reference member data by scanning the reference member; a lens fluctuation calculation process to calculate fluctuation data of the correction data based on the reference member data; and a correction data generation process to generate the correction data by adding the fluctuation data to the white basic data.

An image scanning apparatus, comprising: a scanning device; a reference member; a correction unit; a controller; and a storage device, the scanning device comprising light receiving elements and a lens array, wherein the controller executes: a preparation process and an executive process, the preparation process comprising: a white reference data obtaining process to obtain white reference data by scanning a white reference original; and a white storing process to obtain white basic data by averaging the white reference data of a particular number of adjoining light receiving elements, wherein the executive process comprises: a reference member data obtaining process to obtain reference member data by scanning the reference member; a lens fluctuation calculation process to calculate fluctuation data of the correction data based on the reference member data; and a correction data generation process to generate the correction data by adding the fluctuation data to the white basic data.

An imaging sensor includes multiple light-receiving elements, which are for multiple colors, configured to conduct photoelectric conversion and multiple power supply lines configured to supply a power supply voltage from a power supply source to the light-receiving elements. The light-receiving elements of each of the colors are aligned in one direction. Portions extending between the power supply source and the respective light-receiving elements of the multiple power supply lines are substantially identical in shape on at least a per-color basis.

An imaging sensor includes multiple light-receiving elements, which are for multiple colors, configured to conduct photoelectric conversion and multiple power supply lines configured to supply a power supply voltage from a power supply source to the light-receiving elements. The light-receiving elements of each of the colors are aligned in one direction. Portions extending between the power supply source and the respective light-receiving elements of the multiple power supply lines are substantially identical in shape on at least a per-color basis.

An image processing apparatus includes a processing unit that converts first input image data for a first region and second input image data for a second region to reduce a difference between first region recorded image density and second region recorded image density, and generates dot position data of a dot to be generated in each of the first and second regions based on the dot data after the conversion processing. The acquisition unit acquires edge information indicating a first object pixel edge of an image pixel for the first region and a second object pixel edge of an image pixel for the second region. Based on the acquired edge information, conversion and generation processing are performed in such a manner that a color signal of an edge pixel is increased/reduced to a degree lower than a degree to which a color signal of a non-edge object pixel is increased/reduced.