A lighting device includes a linear light source extending in a first direction and configured to emit light in a second direction intersecting the first direction to an object; a rod lens apart from the linear light source in the second direction and extending in the first direction, the rod lens configured to transmit the light emitted from the linear light source; and a support portion supporting the rod lens and having: a first surface extending in a third direction intersecting the second direction; and a second surface extending in a fourth direction intersecting the second direction and the third direction. The rod lens is in contact with each of the first surface and the second surface.

An image reading apparatus, includes an image sensor, a drive mechanism configured to cause the image sensor to move in a first direction and a second direction opposite to the first direction, a reference plate, and a control unit configured to execute a first reading method of detecting a first reference position by driving the image sensor in the first direction and reading the reference plate, thereafter reading a document by driving the image sensor in the first direction, and a second reading method of detecting a second reference position by driving the image sensor in the second direction and reading the reference plate, and thereafter reading a document by driving the image sensor in the second direction.

There is provided a method of manufacturing an image sensor unit, the image sensor unit including: a linear light source that illuminates a document along a main scanning direction; a rod lens array that includes a plurality of rod lenses arranged in the main scanning direction and condenses a light reflected from the document; and a linear image sensor that receives a light condensed by the rod lens array. When a rod lens having an optically discontinuous portion on a surface and/or interior of the rod lens is included, the rod lens array is arranged such that the optically discontinuous portion is not located toward the document.

In one example, a document scanner has a fixed-position scan bar and a built-in translatable calibration target. The scan bar has a linear array of imaging elements aimed in an imaging direction. The calibration target is spaced apart from and parallel to the linear array, and has a planar surface orthogonal to the imaging direction spanning the length of the linear array. The target is translatable during a calibration in a direction in a plane of the surface.

The present disclosure relates to an image reading device having a highly-accurate structure that enables an easy increase in depth of field, that is, improvement in the depth of the field, without need for a change in basic characteristics of lenses. An overlap preventer (5) disposed between a lens array (1) and a sensor element array (3) to prevent overlap of images formed by lenses (2) is included. A slit section (5) that is the overlap preventer (5) includes multiple slit plates (7) arranged in a main scanning direction and extending in a sub-scanning direction to partition off a space, and the slit plates (7) are fixed to fixing plates (13).

An image sensor unit includes a light condenser that collects light from an object to be read, an image sensor that receives the light collected by the light condenser and outputs an image, and a housing that houses the light condenser and the image sensor. The housing includes a plurality of spacer attachment portions to which a first spacer that keeps a distance between the housing and a mount member can be detachably attached and for which distances between the housing and the mount member in a state where the attached first spacer abuts against the mount member differ from each other.

A light scanning apparatus including: a first holder attached to a housing and configured to hold a first laser light source; a second holder attached to the housing and configured to hold a second laser light source; and a lens to which the laser lights are first incident, wherein the first holder and the second holder are attached to the housing in mutually different positions in a rotation axis direction of a rotary polygon mirror and in an optical axis direction of the lens, so that a first incident light path from the first laser light source to the rotary polygon mirror is placed between a second incident light path from the second laser light source to the rotary polygon mirror and the lens, and the first holder and the second holder overlap one another in the rotation axis direction.

An image sensor unit includes: multiple first light guides that shape light emitted by light sources into a line and emit linear light elongated in longitudinal direction to an object to be read (P); multiple holding members that hold each of the first light guides on a frame; and an image sensor that detects light from the object to be read (P). The multiple first light guides are parallel, and in a range in which the image sensor detects the light from the object to be read (P) in the longitudinal direction of the first light guides, center positions in the main-scan direction of the multiple holding members that hold one first light guide of the multiple light guides and center positions in the main-scan direction of the multiple holding members that hold another light guide different from the one first light guide deviate from each other.

A control system controls an image forming unit that includes a charging device, an image bearer to be charged by the charging device, a light-emitting device array including a plurality of light emitting devices, and a driving causing the light emitting devices to emit light to form a latent image on the image bearer. The control system includes a storage unit, a corrector, and a controller. The storage unit is configured to store a light-amount correction value of each of the light emitting devices. The corrector is configured to correct a pixel value of each pixel in image data, based on the light-amount correction value of each light emitting device stored in the storage unit. The controller is configured to control the driver to cause each light emitting device to emit light based on image data for which a pixel value of each pixel has been corrected.

There is provided a method of manufacturing an image sensor unit, the image sensor unit including: a linear light source that illuminates a document along a main scanning direction; a rod lens array that includes a plurality of rod lenses arranged in the main scanning direction and condenses a light reflected from the document; and a linear image sensor that receives a light condensed by the rod lens array. When a rod lens having an optically discontinuous portion on a surface and/or interior of the rod lens is included, the rod lens array is arranged such that the optically discontinuous portion is not located toward the document.