An image reading apparatus incudes a white reference plate, a reading unit to read the white reference plate; and circuitry to: cause the reading unit to read the white reference plate under a first reading condition before shipment of the image reading apparatus to obtain a first reading value, cause the reading unit to read the white reference plate under a second reading condition same with the first reading condition after replacement of a part of the image reading apparatus after the shipment to obtain a second reading value, and adjust a gray balance coefficient based on the first reading value and the second reading value.

To specify the position of a crease on a document without necessitating an additional configuration, such as a new sensor and a reading angle switching mechanism. An image reading apparatus including: a light emission controlling unit controlling light emission patterns of a first light emitting unit and a second light emitting unit included in a image reading unit; and a determining unit performing determination relating to a crease produced on a document by comparing a first image obtained by reading the document in a first light emission pattern and a second image obtained by reading the document in a second light emission pattern; and wherein the second light emission pattern is different from the first light emission pattern in balance of a quantity of emitted light from the upstream side of a light receiving unit and a quantity of emitted light from the downstream side of the light receiving unit.

An image reading apparatus according to an embodiment includes an image reading unit that generates reference data by reading a reference surface and generates image data by reading a sheet. A reference plate includes the reference surface for generating the reference data for shading correction of the image reading unit and a background surface for background of a sheet to be read to generate the image data. A control unit controls the positions of the image reading unit and the reference plate to be at a first position relative to each other when the reference data is to be generated and at a second position relative to each other when the image data is to be generated. The second position is different from the first position. A shading correction unit performs the shading correction in the image reading unit based on the generated reference data.

An image reading apparatus, including: a conveyance unit configured to convey a document along a conveyance path; a transparent plate provided to the conveyance path; a reading unit configured to read an image of the document passing the transparent plate; a detector configured to detect a foreign substance on the transparent plate from image data output from the reading unit; a light source provided to one end side face of the transparent plate; and a controller configured to control lighting-up of the light source based on a detection result of the detector.

In one example, a document scanner has a fixed-position scan bar and a built-in translatable calibration target. The scan bar has a linear array of imaging elements aimed in an imaging direction. The calibration target is spaced apart from and parallel to the linear array, and has a planar surface orthogonal to the imaging direction spanning the length of the linear array. The target is translatable during a calibration in a direction in a plane of the surface.

An image scanning method applied in an image scanning device capable of scanning a card. Record background values at the time of a card being without being in a scanning channel, and the background values recorded at the time of the card being without being in the scanning channel are regarded as preset values. Before the card is scanned, check whether the background values in the scanning channel conform to the preset values. Drive the card to move a distance Y. Check whether the background values in the scanning channel conform to the preset values. Preset a preset movement distance, check whether a movement distance of the card or a distance of accumulated movements of the card exceeds the preset movement distance. Display that the card is stuck. Stop checking and proceeding an image calibration. Start scanning the card. Complete scanning the card and withdraw the card.

An image reading device includes: a platen on which a document is placed; a platen cover openable and closable with respect to the platen; a cover-open sensor which detects a fact that the open/close angle of the platen cover has passed a predetermined angle from a close state; a CCD line sensor including charge coupled devices (CCD) arranged for recording a variation in distribution for a fixed period of time of incident light when detecting passing of the platen cover; a variation amount calculator which calculates a variation amount of incident light at each distribution point on the basis of a variation in distribution recorded by the CCD line sensor; and a variation amount determination unit which determines whether or not a variation amount calculated by the variation amount calculator exceeds a predetermined threshold.

An image reading apparatus according to an embodiment includes an image reading unit that generates reference data by reading a reference surface and generates image data by reading a sheet. A reference plate includes the reference surface for generating the reference data for shading correction of the image reading unit and a background surface for background of a sheet to be read to generate the image data. A control unit controls the positions of the image reading unit and the reference plate to be at a first position relative to each other when the reference data is to be generated and at a second position relative to each other when the image data is to be generated. The second position is different from the first position. A shading correction unit performs the shading correction in the image reading unit based on the generated reference data.

An image reading apparatus according to an embodiment includes an image reading unit that generates reference data by reading a reference surface and generates image data by reading a sheet. A reference plate includes the reference surface for generating the reference data for shading correction of the image reading unit and a background surface for background of a sheet to be read to generate the image data. A control unit controls the positions of the image reading unit and the reference plate to be at a first position relative to each other when the reference data is to be generated and at a second position relative to each other when the image data is to be generated. The second position is different from the first position. A shading correction unit performs the shading correction in the image reading unit based on the generated reference data.

An image forming system includes an image reading device which reads an image of a sheet conveyed along a conveyance path. The image reading device includes a reading sensor and a moving mechanism. The reading sensor optically reads the image. The moving mechanism moves the reading sensor to a reading position closer to the conveyance path and readable the image and a non-reading position separated from the conveyance path farther than the reading position.