An image reading device includes a placement portion in which a placement surface on which an original document is placed is formed, an imaging portion that is arranged on a center side of the placement surface in an apparatus width direction above the placement surface in an apparatus upward and downward direction and images the original document, a display portion having a display screen of which at least a part is arranged on a far side of the placement surface in an apparatus depth direction and the center side of the placement surface in the apparatus width direction between the placement surface and the imaging portion in the apparatus upward and downward direction, an irradiation portion that is arranged on the center side of the placement surface in the apparatus width direction above the display portion in the apparatus upward and downward direction and irradiates the placement surface with light, and a pair of other irradiation portions that are respectively arranged on both sides of the irradiation portion in the apparatus width direction above the display portion in the apparatus upward and downward direction and irradiate the placement surface with light.

An image scanner including a two-dimensional matrix sensor, a scanning plane defined by the axes, an optical system, an optical axis perpendicular to the scanning plane and coinciding with an axis, a lighting system including at least four light sources that have its own main axis and are positioned so that each light source is adjacent to one side of the scanning plane and illuminates it from a different direction. Each light source is arranged with its own main axis in a plane parallel to a facing mirror-reflecting surface above said facing mirror-reflecting surface and is oriented so as to radiate the scanning plane by specularly reflecting its light beams on the respective mirror-reflecting surface situated on the opposite side of the scanning plane with respect to the light source.

An image forming apparatus includes a post-processing device that folds a paper on which an image is formed, a document scanner that scans a document, and a hardware processor. The hardware processor acquires image data output by the document scanner scanning a region that includes a contour of the document with a folding line formed by being folded by the post-processing device, and determines a relative position of the contour and the folding line of the document based on the image data.

An image sensor unit includes: a linear light source that illuminates a document with a light; a first erecting equal-magnification lens array and a second erecting equal-magnification lens array arranged in the stated order away from the document so as to receive a light reflected from the document and form an erecting equal-magnification image; a slit provided on an intermediate imaging plane between the first erecting equal-magnification lens array and the second erecting equal-magnification lens array; a diffraction grating that disperses a light output from the second erecting equal-magnification lens array; and a linear image sensor that receives a light dispersed by the diffraction grating.

An image scanner including a two-dimensional matrix sensor, a scanning plane defined by the axes, an optical system, an optical axis perpendicular to the scanning plane and coinciding with an axis, a lighting system including at least four light sources that have its own main axis and are positioned so that each light source is adjacent to one side of the scanning plane and illuminates it from a different direction. Each light source is arranged with its own main axis in a plane parallel to a facing mirror-reflecting surface above said facing mirror-reflecting surface and is oriented so as to radiate the scanning plane by specularly reflecting its light beams on the respective mirror-reflecting surface situated on the opposite side of the scanning plane with respect to the light source.

There is provided with an illumination device. The illumination device has a circuit board; a light source movable relative to the circuit board; a rod-like light guide that is configured to guide light from the light source and that is elongated in a longitudinal direction; and a flexible wiring configured to supply electricity from the circuit board to the light source. The light source is capable of moving in the longitudinal direction to reduce fluctuation in distance between the light source and a light receiving surface of the light guide when an end portion of the light guide in the longitudinal direction moves in the longitudinal direction.

An image reading device includes a document conveying device, a first reading module and a control portion. When initial white reference data, that is, an initial value of white reference data, is acquired, the control portion performs white reference data acquisition processing in a plurality of reading modes sequentially, and if it is judged that the white reference data meets a predetermined condition through data judging processing in all the plurality of reading modes, the acquired initial white reference data is set as usable, and if it is judged that the white reference data does not meet the predetermined condition through data judging processing in at least one of the plurality of reading modes, the acquired initial white reference data is set as unusable.

An image sensor unit includes: a light source that illuminates a document; a rod-shaped light guide including a reflection surface that reflects light from the light source and an emission surface provided on a side opposite to the reflection surface that emits light reflected by the reflection surface to the document; a thermal conductor provided so as to cover the reflection surface of the light guide; an image forming element that forms an image of reflected light from the document on a photoelectric conversion element; a sensor substrate on which the photoelectric conversion element is mounted; and a frame including a locator for mounting the light guide.

An image reading apparatus that controls relative positions of a carriage and a document in a first direction using a motor, so as to read an image of the document on a line by line basis, the carriage being mounted with an image sensor and a light source. The image reading apparatus detects an amount of movement caused by the motor in the first direction and generates a first trigger signal in response to input of a synchronization signal generated in accordance with the detected amount of movement, the first trigger signal instructing to start accumulation of charge in the image sensor, and, after a predetermined amount of time since the synchronization signal used for generating the first trigger signal is input, generates a second trigger signal, the second trigger signal instructing to end accumulation of the charge being accumulated in the image sensor.

An image reading apparatus includes: a reading unit configured to read an image of an original and output an image signal; and a white reference plate to be used for shading correction. The image reading apparatus drives the reading unit with maximum power consumption for a predetermined time period and thereafter drives the reading unit with reduced power consumption. The image reading apparatus causes the reading unit with reduced power consumption to read the white reference plate and generates shading data to be used for the shading correction. After that, the image reading apparatus causes the reading unit to read an original and corrects a reading result of the original based on the shading data.