Abstract: The diffusing member includes a diffusing surface with protruding portions arrayed in a first direction. The protruding portions include a first group of protruding portions in which tops thereof are arranged on a first line parallel to the first direction when they are projected on a first cross section parallel to the first direction.

Abstract: An image reading apparatus according to the present invention includes: a conveyor which conveys an original in a first direction; a light transmitting member which is provided with coating in a first region of a surface facing the original; a reading unit which reads an image at a reading position of the original through the light transmitting member; and a controller which performs processing on the image and which changes the reading position by moving the reading unit when abnormality is detected in the processing. The coating includes a silicon-containing perfluoropolyether compound. An electrically-conductive member is provided in a second region located on the surface of the light transmitting member, upstream of the first region in a conveyance direction of the original. A contact angle of the coating at a position corresponding to the reading position in the first region is appropriately set.

Abstract: An image reading apparatus according to the present invention includes: a conveyor which conveys an original in a first direction; a light transmitting member which is provided with coating in a first region of a surface facing the original; a reading unit which reads an image at a reading position of the original through the light transmitting member; and a controller which performs processing on the image and which changes the reading position by moving the reading unit when abnormality is detected in the processing. The coating includes a silicon-containing perfluoropolyether compound. An electrically-conductive member is provided in a second region located on the surface of the light transmitting member, upstream of the first region in a conveyance direction of the original. A contact angle of the coating at a position corresponding to the reading position in the first region is appropriately set.

Abstract: Provided is a light guiding unit including: a light guiding member including an incident surface, an exit surface elongated in a first direction, and a light guiding surface opposed to exit surface; and a diffusion member opposed to light guiding surface, in which: light entering the light guiding member from incident surface is guided via light guiding surface and diffusion member to exit surface, and exits from exit surface to illuminate the original; the light guiding member further includes a plurality of prisms arrayed in first direction on light guiding surface on a side opposed to diffusion member; each of prisms has a rectangular shape in a first section; and each of prisms satisfies the following condition: W tan(sin?1(1/n))?H?2W, where W and H represent a width and a height of each of prisms in the first section, respectively, and n represents a refractive index of the light guiding member.

Abstract: Provided is a light guiding unit including: a light guiding member including an incident surface, an exit surface elongated in a first direction, and a light guiding surface opposed to exit surface; and a diffusion member opposed to light guiding surface, in which: light entering the light guiding member from incident surface is guided via light guiding surface and diffusion member to exit surface, and exits from exit surface to illuminate the original; the light guiding member further includes a plurality of prisms arrayed in first direction on light guiding surface on a side opposed to diffusion member; each of prisms has a rectangular shape in a first section; and each of prisms satisfies the following condition: W tan(sin?1(1/n))?H?2W, where W and H represent a width and a height of each of prisms in the first section, respectively, and n represents a refractive index of the light guiding member.

Abstract: Provided is an image reading apparatus that can inhibit occurrence of a bright spot line image due to microstructures of a light guide. An image reading apparatus satisfies: 45????????/n (0????max); and 45?????? (??max???0), where ? is an angle (deg.) between a surface of original and a reflecting surface of a microstructure reflection surface of a light guide, ? is a half angle of view (deg.) of an imaging forming lens, ?max (?max>0) is a maximum value (deg.) of the half angle of view of the imaging forming lens on an LED light source side with respect to a reading optical axis of the imaging lens, ??max is a maximum value (deg.) of the half angle of view of the imaging lens on a side opposite to the LED light source with respect to the reading optical axis, n is a refractive index of the light guide, and ?=sin?1(1/n).

Abstract: Provided is an image reading apparatus that can inhibit occurrence of a bright spot line image due to microstructures of a light guide. An image reading apparatus satisfies: 45????????/n (0????max); and 45??????(??max???0), where ? is an angle (deg.) between a surface of original and a reflecting surface of a microstructure reflection surface of a light guide, ? is a half angle of view (deg.) of an imaging forming lens, ?max (?max>0) is a maximum value (deg.) of the half angle of view of the imaging forming lens on an LED light source side with respect to a reading optical axis of the imaging lens, ??max is a maximum value (deg.) of the half angle of view of the imaging lens on a side opposite to the LED light source with respect to the reading optical axis, n is a refractive index of the light guide, and ?=sin?1(1/n).

Abstract: An illumination device and an image reading apparatus having improved heat resistance and spectral characteristics are provided. An illumination device used in an image reading apparatus that moves relative to a read area of a document includes: a light source; a light guide including an incident surface on which light from the light source is incident and an exit surface from which light from the light source exits; and a spectroscopic unit that is provided between the light source and the light guide and includes, on a surface of a glass substrate facing the light source, a multi-layer film for reflecting infrared light toward the light source.

Abstract: An illumination device and an image reading apparatus having improved heat resistance and spectral characteristics are provided. An illumination device used in an image reading apparatus that moves relative to a read area of a document includes: a light source; a light guide including an incident surface on which light from the light source is incident and an exit surface from which light from the light source exits; and a spectroscopic unit that is provided between the light source and the light guide and includes, on a surface of a glass substrate facing the light source, a multi-layer film for reflecting infrared light toward the light source.

Abstract: An illumination apparatus for use in an image reading apparatus that forms a reduction image of a read area of an original on an image pickup element by an imaging optical system, includes: a light source illuminating the original; and a light guide guiding light to the original; wherein the light guide has a first surface on which light is incident or that diffuses light, a second surface from which light exits toward the read area, and a third and fourth surfaces arranged between the first and second surfaces in a sub-scanning section perpendicular to a longitudinal direction of the light guide, the third surface arranged on a side closer to an optical axis of the imaging optical system, and the fourth surface arranged on a side farther from the optical axis, wherein the third and fourth surfaces are reflective surfaces having the same paraxial power which is appropriately set.

Abstract: An illumination apparatus for use in an image reading apparatus that forms a reduction image of a read area of an original on an image pickup element by an imaging optical system, includes: a light source illuminating the original; and a light guide guiding light to the original; wherein the light guide has a first surface on which light is incident or that diffuses light, a second surface from which light exits toward the read area, and a third and fourth surfaces arranged between the first and second surfaces in a sub-scanning section perpendicular to a longitudinal direction of the light guide, the third surface arranged on a side closer to an optical axis of the imaging optical system, and the fourth surface arranged on a side farther from the optical axis, wherein the third and fourth surfaces are reflective surfaces having the same paraxial power which is appropriately set.