A two-sided scanning device includes a first image scanning module, a second image scanning module, a first scanning background component, a first brightness calibration component, a second scanning background component, and a second brightness calibration component. When the second image scanning module moves relative to the first image scanning module to a scanning position, the second image scanning module drives the first scanning background component to move relative to the first image scanning module, so that the first image scanning module and the second image scanning module are aligned with the first scanning background component and the second scanning background component, respectively. Therefore, the first scanning background component and the second scanning background component can be scanning backgrounds for the first image scanning module and the second image scanning module to generate a scanning image of an object with a size corresponding to an actual size of the object.

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.

Provided are an light scanning device capable of adjusting the position of optics and an image forming apparatus including the light scanning device. The light scanning device includes first and second light sources configured to emit first and second light beams, respectively; optics including first and second lenses for transmitting the first and second light beams therethrough and a lens holder configured to support the second lens; and a housing configured to support the first and second light sources and the optics, wherein the first and second light sources and the first lens are supported to be fixed to the housing, and the second lens is supported to be able to move with respect to the first lens.

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.

A sensor mounting structure includes a positioning member, a holding member, and a biasing member. The positioning member is a mounting reference of a sensor. The holding member is attachable to and detachable from the positioning member so as to form a space in which the sensor is disposed with respect to the positioning member. The biasing member includes an arched part which is overhung between a pair of engaging parts engaging with the holding member. The biasing member, while the holding member is attached to the positioning member, elastically deforms the arched part that is sandwiched between the holding member and the sensor that is disposed in the space so as to bias the sensor to the positioning member.

A image reading apparatus includes a first placement unit, a second placement unit, a first reading unit, a second reading unit, a rotating mechanism, and a switch-over mechanism that switches over the first placement unit and the second placement unit between a horizontal state and an inclined state. The rotating mechanism rotates the first reading unit and the second reading unit, so that, in the horizontal state, the first image reading unit and the second image reading unit read a medium placed on the first placement unit and a medium placed on the second placement unit respectively, and, in the inclined state, the first image reading unit and the second image reading unit read a medium placed on the second placement unit and a medium placed on the first placement unit respectively.

A image reading apparatus includes a first placement unit, a second placement unit, a first reading unit, a second reading unit, a rotating mechanism, and a switch-over mechanism that switches over the first placement unit and the second placement unit between a horizontal state and an inclined state. The rotating mechanism rotates the first reading unit and the second reading unit, so that, in the horizontal state, the first image reading unit and the second image reading unit read a medium placed on the first placement unit and a medium placed on the second placement unit respectively, and, in the inclined state, the first image reading unit and the second image reading unit read a medium placed on the second placement unit and a medium placed on the first placement unit respectively.

An image reading apparatus includes a carriage, a drive mechanism, an imaging device, a controller, and a first white reference plate. The controller controls the drive mechanism, thereby moving the carriage to a search start position, located on a side of a document setting region with respect to a region occupied by the first white reference plate, decides, on a basis of image data on an outer side of the document setting region in the main scanning direction, sequentially read by the imaging device while the carriage is being moved in a first direction, from the search start position toward the region occupied by the first white reference plate, whether a read image is white, and positions the carriage at a home position, by moving the carriage from a position thereof when the read image was decided as white, by a predetermined distance in the first direction.