An image reading apparatus includes a light source to emit at least light in a first wavelength range and light in a second wavelength range, a background member having different light reflectances in the first and second wavelength ranges, an imaging device, and circuitry. The imaging device receives reflected light from the background member irradiated with the light in the first wavelength range, and generates first read information. The imaging device further receives reflected light from the background member irradiated with the light in the second wavelength range, and generates second read information. The circuitry detects presence or absence of a first foreign substance based on a difference in reading level of the first read information generated by the imaging device; and detect presence or absence of a second foreign substance based on a difference in reading level of the second read information generated by the imaging device.

An image reading optical system includes an image reading unit including plural reading elements that are arranged in a first direction, a first reflective optical system configured to reflect reflection light which is irradiation light emitted from a light source and reflected on an object to be read, a second reflective optical system configured to condense the reflection light reflected on the first reflective optical system to the image reading unit, and an aperture stop including a plate shaped member formed with an aperture configured to regulate the reflection light reflected on the first reflective optical system in the first direction, the plate shaped member including at least one plate shaped piece bent at a preset angle with respect to the aperture along a tangent line of the aperture in the first direction.

A light guide includes a first exit portion emitting first exiting light, a second exit portion emitting second exiting light in a different direction than the first exiting light, and a reflecting portion reflecting light entering the light guide to each of the first and second exit portions. The first and second exit portions respectively have first and second curved surfaces each having a convex cross section perpendicular to the long axis direction. The second exit portion is connected to the first exit portion in the direction perpendicular to the long axis direction. The reflecting portion is provided, in a plane facing the first exit portion and the second exit portion, at a position shifted in the direction perpendicular to the long axis direction from a position where a normal to the plane passes through a connection portion between the first and second exit portions.

A reading apparatus includes an irradiation unit that performs irradiation with light, a light receiving unit that receives light reflected from an object to be imaged, a first optical path in which specularly reflected light, which is obtained as light emitted by the irradiation unit is reflected from a first reflection surface so that a front surface of the object to be imaged in an irradiation region is irradiated with the reflected light, and the reflected light is specularly reflected from the front surface of the object to be imaged, is guided to the light receiving unit as a read image, a second optical path in which diffusely reflected light, which is obtained as the light emitted by the irradiation unit is reflected from a second reflection surface so that the front surface of the object to be imaged in the irradiation region is irradiated with the reflected light, and the reflected light is diffusely reflected from the front surface of the object to be imaged, is guided to the light receiving unit as a read image, and a switching section that switches between the first optical path and the second optical path by rotating the irradiation unit.

An illumination apparatus includes a light source and an elongated light guide, wherein the light guide includes an emission surface that emits light from the light source and a reflection surface that reflects the light to the emission surface, the reflection surface includes a plurality of diffusion portions that diffuse the light, the diffusion portions have a shape of part of a sphere recessed from the reflection surface, a depth of the diffusion portions from the reflection surface is equal to or greater than 16.5% and equal to or smaller than 50% of a diameter of the sphere, and a width of the diffusion portions is equal to or greater than 0.1 mm and equal to or smaller than 50% of a width of the reflection surface.

An image reading apparatus includes a light source to emit at least light in a first wavelength range and light in a second wavelength range, a background member having different light reflectances in the first and second wavelength ranges, an imaging device, and circuitry. The imaging device receives reflected light from the background member irradiated with the light in the first wavelength range, and generates first read information. The imaging device further receives reflected light from the background member irradiated with the light in the second wavelength range, and generates second read information. The circuitry detects presence or absence of a first foreign substance based on a difference in reading level of the first read information generated by the imaging device; and detect presence or absence of a second foreign substance based on a difference in reading level of the second read information generated by the imaging device.

A sheet feeding device includes a stacking tray for stacking a sheet; a sheet detector for detecting presence/absence of the sheet on the stacking tray; a feeder for feeding the sheet detected by the sheet detector; an LED, provided adjacent to the sheet stacked on the stacking tray, for emitting light; a display, provided substantially in parallel with an optical axis of the LED, for being illuminated by the light emitted from the LED; a reflector, provided opposed to the display portion, for reflecting and scattering the light emitted by the LED, toward the display; and a controller for controlling emission of the light of the LED on the basis of a signal outputted by the sheet detector.

An imaging device includes a light source unit located so as to be inclined with respect to a medium conveying surface or a medium placing surface. The light source unit includes a light emitting element, a light guide provided with the light emitting element on a first end surface side, to guide light emitted from the light emitting element in a predetermined direction, and emit the light toward the medium from an emitting surface extending in the predetermined direction, and a reflector located around the light guide other than the emitting surface. The light guide includes a light diffusing surface on an opposite side to the emitting surface. The reflector does not cover a second end surface opposite to the first end surface of the light guide. A medium side surface of the reflector is located so as to protrude from the second end surface of the light guide.

An image reading apparatus for reading an image of an original includes an illumination portion for illuminating the original with light, a reflection member including a reflecting surface for reflecting the light from the original; a converting portion for photoelectrically converting the light reflected by the reflection member, and a casing for accommodating the reflection member. The casing is provided with an opening which is open to an outside of the casing. A surface of the reflecting member opposite from the reflecting surface and a portion defining the opening are bonded to each other with an adhesive.

An imaging device includes a light source unit located so as to be inclined with respect to a medium conveying surface or a medium placing surface. The light source unit includes a light emitting element, a light guide provided with the light emitting element on a first end surface side, to guide light emitted from the light emitting element in a predetermined direction, and emit the light toward the medium from an emitting surface extending in the predetermined direction, and a reflector located around the light guide other than the emitting surface. The light guide includes a light diffusing surface on an opposite side to the emitting surface. The reflector does not cover a second end surface opposite to the first end surface of the light guide. A medium side surface of the reflector is located so as to protrude from the second end surface of the light guide.