An image reading device includes an image reader to read image data from a document; a density reference member facing the image reader; a movable mechanism to movably support the density reference member in a movable state; a lock mechanism to lock the movable mechanism to fix a position of the density reference member in a fixed state; and circuitry configured to cause the image reader to read the image data from the document while the density reference member is at a first position in the fixed state; cause the image reader to read shading data from the density reference member while the density reference member is at a second position different from the first position in the movable state; generate reference data used for a shading correction from the shading; and perform the shading correction on the image data, using the reference data.

An image scanner includes a transparent plate, a scanning device, a driving device, a positioning member, a light absorbing portion and a white reference portion. The transparent plate has an original placing surface. The scanning device irradiates an original with light by means of a light source and scans reflected light from the original. The driving device reciprocates the scanning device along the transparent plate. The positioning member positions the original placed on the original placing surface of the transparent plate. The light absorbing portion, which is disposed on the original placing surface side of the positioning member and at substantially a central portion of the positioning member in moving directions of the scanning device, absorbs ambient light entering to the original placing surface side of the positioning member through the transparent plate. The white reference portion is provided to the original placing surface side of the positioning member.

An image scanner includes a transparent plate, a scanning device, a driving device, a positioning member, a light absorbing portion and a white reference portion. The transparent plate has an original placing surface. The scanning device irradiates an original with light by means of a light source and scans reflected light from the original. The driving device reciprocates the scanning device along the transparent plate. The positioning member positions the original placed on the original placing surface of the transparent plate. The light absorbing portion, which is disposed on the original placing surface side of the positioning member and at substantially a central portion of the positioning member in moving directions of the scanning device, absorbs ambient light entering to the original placing surface side of the positioning member through the transparent plate. The white reference portion is provided to the original placing surface side of the positioning member.

An image reading apparatus includes a light source and a movable light reflecting surface provided to be capable to move to a first position to reflect light from the light source. The image reading apparatus includes a cam to move the light reflecting surface and having a first portion, a driving module for providing a driving force, and a transmission member for rotating the cam with the driving force provided by the driving module, the transmission member having a second portion, wherein the transmission member moves the light reflecting surface to a predetermined position by rotating the cam, and by bringing the second portion into contact with the first portion to hold the light reflecting surface at the predetermined position when there is no driving force.

An image reading apparatus includes a gray reference member, a reading unit, an adjusting unit, a calibration unit, a storage unit, and a control unit. The control unit is configured to execute a first preprocessing and a second preprocessing. The first preprocessing includes: acquiring first black data from one line worth of image data; acquiring white data; calculating white-black difference data; acquiring first light gray data; and calculating first light gray-black difference data. The second processing includes: acquiring second black data from the one line worth of the image data; acquiring second light gray data; calculating second light gray-black difference data; calculating a change ratio by dividing the second light gray-black difference data by the first light gray-black difference data; and calculating calibration data by multiplying the white-black difference data by the change ratio. Shading of the image data is calibrated in response to the calibration data.

A movement unit moves a reading unit in a first direction and a second direction. A control unit controls the movement unit so that the reading unit is positioned in a predetermined region in a case when a transition is made from an operation mode to a non-operation mode and controls the movement unit to cause the reading unit to move from the predetermined region to a position at which a white reference plate can be read in a case when a transition is made from the non-operation mode to the operation mode. The control unit causes movement of the reading unit by the movement unit to stop when a movement amount of the reading unit measured by a measurement unit becomes a movement amount corresponding to a distance from the boundary to a position at which a white reference plate can be read.

A scanner includes a transport mechanism that continuously transports a plurality of documents, a sensor, a control unit that performs correction of a read image which the sensor reads by using a correction value, a calculation unit that calculates the correction value based on a result from which the sensor reads a reference region between the documents, and a storage unit that sequentially stores the correction value in any of a plurality of storage regions, in which the control unit switches the storage region where the correction value used for the correction is read out to the storage region where the calculated correction value is stored, if storing of the calculated correction value is completed.

In an image reader, a controller acquires a set of first black data for each pixel in a line by reading one line worth of image via a light receiver with a light source being turned off when a detector detects that a cover is in an open state. Subsequently, the controller acquires a set of white data for the each pixel in the line by reading a white reference member via the light receiver with the light source emitting light when the detector detects that the cover is in the open state. The controller calculates a set of correction data for the each pixel in the line by subtracting the set of first black data of the each pixel from the set of first white data of the each pixel. The set of correction data is used in a shading correction.

An image reading device, which may be incorporated in an image forming apparatus, includes an image reader, a color reference body, a biasing body, a reading gap forming device, and a driving device. The image reader reads an image of an original document. The color reference body has a white reference face to position facing the image reader within a predetermined range in a document width direction. The biasing body biases the color reference body to the image reader. The reading gap forming device forms a reading gap while receiving a biasing force from the biasing body on the outside of the predetermined range. The driving device has a force drive transmission body engaged with a center of the color reference body in the document width direction and drives the color reference body in the document width direction at the center via the force drive transmission body.

An image reading apparatus includes a light emitting element, a luminance calculating unit, a light amount setting unit, and a storing unit. The light amount setting unit, in each line period, causes the light emitting element to emit a light with gradually changing a reference light amount from a reference light amount set as a default value from among a plurality of reference light amounts stored in the storing unit, identifies a reference light amount so that the luminance calculated by the luminance calculating unit is within a predetermined range, sets the identified reference light amount as a default value for the next line period, and causes the storing unit to store that reference light amount.