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.

Provided is a reading device including: a first emitting unit configured to emit light; an optical path unit having a reflection surface configured to reflect a part of light emitted from the first emitting unit, and an optical path configured to guide the part of light from the reflection surface to an original; and an image sensor that generates an image from specular reflection of the part of light guided by the optical path from the original.

An image reading apparatus includes a light source, a light receiving unit, and an optical system. The light receiving unit includes a plurality of light receiving elements. The optical system includes a plurality of optical components for splitting the light reflected from the object to be read, and guiding the split light to each of the plurality of light receiving elements. The plurality of optical components include a splitting component that splits the light reflected from the object to be read in a direction corresponding to a main direction, and a common component provided with a common portion. The common portion has an optically acting area causing a common effect on the tight split by the splitting component. A cross sectional shape of the optically acting area orthogonal to a direction corresponding to the main direction is the same shape along the direction corresponding to the main direction.

In an example embodiment, an image processing system can be implemented, which includes a printing surface and a prism that splits light from an input light source into two parallel light beams indicative of a signal image. Two or more DMDs (Digital Micromirror Devices) can be utilized, wherein the two parallel light beams are directed to the DMDs for image processing, such that as the two parallel light beams are reflected out onto the printing surface, the two parallel light beams are recombined into a single image, thereby enabling heat dissipation while stitching said output of said at least two digital micromirror devices to a usable video path.

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.

An illuminating device according to an embodiment included in an image reading apparatus and an image forming apparatus includes light source portions, light-guiding members for illuminating an illumination target from an elongated light emitting face that extends in a longitudinal direction, by guiding light from the light source portions, and holding members for holding the light-guiding members. The holding members include holding portions for removably holding the light-guiding members, and tilted portions that reflect light emitted from the light emitting face, the tilted portions extending from a front end on the light emitting face side of the holding portions, obliquely widening with increasing distance from the light-guiding members.

A light-guide member includes a light-incident surface formed at an end portion of the light-guide member in a first direction, a light-emitting surface that is elongated in the first direction and that includes first and second light-emitting regions, which cause light to be emitted in different directions in a first cross section that is perpendicular to the first direction, a common deflecting portion that deflects light from the light-incident surface and causes the light to be emitted from the first and second light-emitting regions to the outside, and first and second protruding portions each of which is located on one of two sides of the deflecting portion in the first cross section, the first and second protruding portions protruding in a direction away from the light-emitting surface with respect to the deflecting portion.

An image reading apparatus includes a light source that emits light in a main scanning direction to a subject to be read, a light receiving unit that receives light reflected by the subject to be read, and an optical system that images the light reflected by the subject to be read and guides the light to the light receiving unit. The optical system includes a reflector mirror that reflects the light reflected by the subject to be read, and an optical element that is disposed adjacent to the reflector mirror and images the light reflected by the subject to be read. The optical element is held by the reflector mirror.

An illuminating device (210) according to an embodiment of the invention included in an image reading apparatus (100) and an image forming apparatus (D) includes light source portions (211a1), (211b1), (211a2) and (211b2), light-guiding members (213a) and (213b) for illuminating an illumination target (G) from an elongated light emitting face (M) that extends in a longitudinal direction (Y), by guiding light from the light source portions, and holding members (216a) and (216b) for holding the light-guiding members. The holding members include holding portions (2161a) and (2161b) for removably holding the light-guiding members, and tilted portions (2162a) and (2162b) that reflect light emitted from the light emitting face (M), the tilted portions extending from a front end on the light emitting face (M) side of the holding portions, obliquely widening with increasing distance from the light-guiding members.

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.