An image reading device includes light guides (5, 6) that emit light to an object to be read, a lens body (8) that condenses reflected light, a light receiver (13) that receives the reflected light, a sensor board (24) on which is mounted the light receiver (13), a lens holder (11), and a housing (9) that houses or holds these components. The lens holder (11) includes a holder bottom (11g), light guide positioners (11a, 11b) and lens body holders (11e, 11f). In the lens holder (11), the lens body (8) is attached between the lens body holders (11e, 11f), the sensor board (24) is attached to the holder bottom (11g) such that the light receiver (13) aligns with an optical axis of the lens body (8), and the light guides (5, 6) are attached to the light guide positioners (11a, 11b). A surface of each light guide positioner (11a, 11b) that faces the corresponding light guide (5, 6) to be attached has at least a portion having a same shape a s a shape of a surface of the light guide.

In a reading device, a light transmissive member has a front surface on which an original is placed. A peripheral member is adjacent to the light transmissive member, and includes a back surface in which a reference hole is formed. The reference hole includes a first edge and a second edge intersecting with each other. A reading sensor faces the back surface of the light transmissive member and the back surface of the peripheral member. The controller controls the reading sensor to read a reading range including the reference hole to obtain a read image, and determines a reference position in the reading range based on the read image. The reference position is determined to an intersection between the first edge and the second edge. The controller sets a reading start position based on the reference position.

There is provided with an illumination device. The illumination device has a circuit board; a light source movable relative to the circuit board; a rod-like light guide that is configured to guide light from the light source and that is elongated in a longitudinal direction; and a flexible wiring configured to supply electricity from the circuit board to the light source. The light source is capable of moving in the longitudinal direction to reduce fluctuation in distance between the light source and a light receiving surface of the light guide when an end portion of the light guide in the longitudinal direction moves in the longitudinal direction.

An image sensor unit includes: a light source that illuminates a document; a rod-shaped light guide including a reflection surface that reflects light from the light source and an emission surface provided on a side opposite to the reflection surface that emits light reflected by the reflection surface to the document; a thermal conductor provided so as to cover the reflection surface of the light guide; an image forming element that forms an image of reflected light from the document on a photoelectric conversion element; a sensor substrate on which the photoelectric conversion element is mounted; and a frame including a locator for mounting the light guide.

An image reading apparatus includes a substrate, a light guiding member, an image reading portion, and a supporting member. The light guiding member has a first contact surface and a second contact surface. The supporting member has a third contact surface supporting the first contact surface and a fourth contact surface supporting the second contact surface. In a cross section crossing the longitudinal direction, at least one of the first contact surface of the light guiding member and the third contact surface of the supporting member is a curved surface. In the cross section crossing the longitudinal direction, at least one of the second contact surface of the light guiding member and the fourth contact surface of the supporting member is a curved surface.

An image processing device may include an image acquisition part configured to acquire image data including an information recording medium captured under irradiation of light, an angle calculation part configured to calculate an inclination angle of the information recording medium based on the image data, an apex calculation part configured to calculate coordinates of respective apexes corresponding to a quadrangle of the information recording medium based on the image data, and an angle correction part configured to correct the coordinates of the respective apexes calculated by the apex calculation part with the inclination angle, and the angle correction part is further configured, for each pixel within a quadrangle formed by respective corrected apexes, to acquire a pixel value of a pixel of the image data located at a coordinate obtained by reversely converting a coordinate of the each pixel with the inclination angle to prepare corrected image data.

Provided are a reader and an ink-jet recording device with which it is possible to maintain the accuracy of reading a document continuously for a longer time. The reader is provided with a detection unit for detecting light from the surface of an object to be read and a housing for shutting the detection unit tight, the housing having a window for allowing the light from the surface of the object to be read to enter the inside via a light permeable member, the window being provided at a position in the housing more separate from the surface of the object to be read than is a nearest surface facing the surface of the object to be read in the shortest distance.

An information reading may include an imaging element; a transparent placing member on which the information recording medium is placed; a first illuminator configured to irradiate a back side of the information recording medium placed on the placing member, with light; a second illuminator configured to irradiate a top side of the information recording medium placed on the placing member, with light; a first optical system configured to read information recorded on the back side of the information recording medium placed on the placing member; a second optical system configured to read information recorded on the top side of the information recording medium placed on the placing member; and an image-forming optical system configured to cause light passing through the first optical system to form an image onto the imaging element and cause light passing through the second optical system to form an image on the imaging element.

An illumination device includes a light guide member having a bar-like shape and a light source disposed so as to face an end surface of the light guide member. The illumination device guides light from the light source in the light guide member and emits the light from a light emission surface of the light guide member formed in a longitudinal direction of the light guide member. The light emission surface includes a first light diffusing portion that is formed in a first portion near the light source and that has a protruding/recessed shape, and a second light diffusing portion that is formed in a second portion adjacent to an end of the first light diffusing portion, the end being away from the light source. The second light diffusing portion has a protruding/recessed shape and has lower light diffusivity than the first light diffusing portion.

An objective of the present disclosure is to obtain a light guide and an image reading apparatus capable of efficiently irradiating an object to be irradiated (1). The light guide and the image reading apparatus include a rod-shaped light guide main body (2) extending in the longitudinal direction, a first end face (3) that is an end face of the light guide main body (2) along the transverse direction, a light scattering pattern (5) that scatters light that enters from the first end face (3) and is guided inside the light guide main body (2), and a light emission surface portion (6) formed on the light guide main body along a longitudinal direction, the light emission surface portion (6) being a surface from which the light scattered at the light scattering pattern (5) is emitted to outside the light guide main body (2) after being reflected on a wall surface of the light guide main body (2). The light emission surface portion (6) includes a first light emission surface (6a) that is disposed near the first end face (3) in the longitudinal direction and a second light emission surface (6b) that is contiguous with the first light emission surface (6a) in the longitudinal direction. A width of the first light emission surface (6a) in the transverse direction is shorter than a width of the second light emission surface (6b) in the transverse direction.