An optical device includes a light source unit, an optical member, and a holder formed by a single member. The light source unit includes a light source that emits light in a first direction and has a first positioning surface orthogonal to the first direction. The optical member is disposed to be separated from and opposed to the light source unit in the first direction and has an incident surface, an emission surface, and a second positioning surface. The holder has a third positioning surface and a fourth positioning surface, holds the light source unit in a state in which the first positioning surface of the light source unit is set in surface contact with the third positioning surface, and holds the optical member in a state in which the second positioning surface of the optical member is set in surface contact with the fourth positioning surface.

An image reading device, which is included in an image forming apparatus and used to perform a method of reading images, includes an image reading body configured to read one of a recording medium and the recording medium together with a background area adjacent to the recording medium, a moving body disposed facing the image reading body, and a reference body as a reference in shading correction. The moving body is configured to hold the recording medium and the reference body in a direction intersecting a sheet conveying direction of the recording medium such that the recording medium and the reference body contact to and separate from the image reading body.

An illuminating device capable of stably illuminating an irradiated object such as a document while suppressing light loss with a simply structure is provided. An LED array and a reflective plate are disposed sandwiching a slit (St) through which light reflected by a document MS passes and a light-guiding member is disposed on the side of the LED array. The light-guiding member includes a direct emission unit disposed between an illumination range y centered on a document reading position and the LED array and an indirect emission unit disposed between the reflective plate and the LED array, a light incidence face of the direct emission unit and a light incidence face of the indirect emission unit are disposed at mutually different position around the LED array, and the LED array is disposed on a side of an interior angle formed by the light incidence faces.

An image forming apparatus in which at least part of an image scanner is disposed in an area below an original discharge unit and above an image forming unit.

A reading apparatus that reads a sheet includes: a first light emitting diode (LED) configured to emit light with a specific wavelength; a light emitting element including a second LED configured to emit light with the specific wavelength and a phosphor configured to be excited by the light emitted from the second LED; a line sensor configured to generate a reference signal according to a quantity of received light emitted from the first LED and reflected off the sheet, and also generate an image signal according to a quantity of received light emitted from the light emitting element and reflected off the sheet; and a controller configured to generate an image representing the sheet from a differential result obtained by removing a component corresponding to the reference signal from the image signal.

An image reading apparatus includes a light irradiator, an optical system and a photoelectric converter. The optical system includes a reflection mirror unit and an aperture unit. The reflection mirror unit includes first and second reflection areas successively provided in a main scanning direction. The aperture unit includes a light shielding portion and first and second light passing holes for allowing the passage of the light reflected by each of the first and second reflection areas. The photoelectric converter includes a light receiving surface having first and second light receiving areas configured to receive the light passed through each of the first and second light passing holes and successively arranged in the main scanning direction. A length of the light receiving surface along the main scanning direction is set to be equal to or longer than that of the image reading area along the main scanning direction.

An image sensor includes: a lens configured to focus light irradiated toward an object to be read and reflected by the object to be read; a sensor configured to receive light focused by the lens; a sensor board configured to mount thereon the sensor; a board retaining plate, having a casing attachment surface extending in the X direction and a sensor board attachment reference surface that is in contact with the +Y side of the sensor board and is formed in a side surface of the casing attachment surface, and configured to retain the sensor board; and a first casing configured to fix or retain the board retaining plate by fastening of a surface of the casing attachment surface.

An illuminating device capable of stably illuminating an irradiated object such as a document while suppressing light loss with a simply structure is provided. An LED array and a reflective plate are disposed sandwiching a slit (St) through which light reflected by a document MS passes and a light-guiding member is disposed on the side of the LED array. The light-guiding member includes a direct emission unit disposed between an illumination range y centered on a document reading position and the LED array and an indirect emission unit disposed between the reflective plate and the LED array, a light incidence face of the direct emission unit and a light incidence face of the indirect emission unit are disposed at mutually different position around the LED array, and the LED array is disposed on a side of an interior angle formed by the light incidence faces.

An image reading apparatus includes: three or more light sources configured to each emit light; a light receiving unit including a common light receiving surface configured to detect each light emitted; and an image generation unit configured to cause the three or more light sources to be switched over in a predetermined order and emit the corresponding light, and generate an image read from a document, wherein at least one of the three or more light sources includes a white light source and an optical filter, and the optical filter is configured such that a half-value width of a wavelength with respect to a maximum intensity of a spectral characteristic of the emitted light after transmission is wider than a half-value width of a wavelength with respect to a maximum intensity of the spectral characteristic of the light emitted from at least one of the other light sources.

A document reader system configured to capture an image of a document is described. The document reader system includes a document reader having a transparent scan area configured to receive the document on a first side of the transparent scan area. A light source positioned on a second side of the transparent scan area opposite the first side is configured to emit light towards the transparent scan area. An image sensor positioned on the second side of the transparent scan area is configured to capture images of the document on the first side of the transparent scan area. A processor is configured to process a first image of the document captured while the light source provides a first illumination output and a second image of the document captured while the light source provides a second illumination output to generate a third image of the document having corrected ambient light effects.