An image reading device includes: an area sensor in which color filters of three colors of R, G, and B are arranged in a Bayer array and a light receiving amount is detected by a light receiving element for each color filter; and a hardware processor that: reads a document by using the light receiving elements in a first group in the area sensor, reads the document by using the light receiving elements in a second group in the area sensor, at a region shifted by ½ pixels in a sub-scanning direction from a reading region of the light receiving elements in the first group, and interpolates R-color read data and B-color read data using G-color read data and synthesizes image data having a resolution twice the resolution of the area sensor.

An image reading device includes: an area sensor in which color filters of three colors of R, G, and B are arranged in a Bayer array and a light receiving amount is detected by a light receiving element for each color filter; and a hardware processor that: reads a document by using the light receiving elements in a first group in the area sensor, reads the document by using the light receiving elements in a second group in the area sensor, at a region shifted by ½ pixels in a sub-scanning direction from a reading region of the light receiving elements in the first group, and interpolates R-color read data and B-color read data using G-color read data and synthesizes image data having a resolution twice the resolution of the area sensor.

An image reading device includes a lens array including lenses arranged in a main scanning direction and forming an erect unmagnified optical system to converge light from a reading target, a holder holding the lens array, a light receiver to receive the light converged by the lenses, and slit units. Each slit unit includes three or more light shielding plates each separating an optical path of one lens from an optical path of another lens between the lens array and the light receiver, and side plates disposed on two sides of the light shielding plates in a direction intersecting the main scanning direction and connecting two adjacent light shielding plates. The slit units are arranged in the main scanning direction, and each two adjacent slit units are arranged with a space therebetween for one optical path of one lens.

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 lighting device (23) irradiates a web under conveyance with light. The lighting device includes a light source (43), and an irradiation port (61) configured to open linearly in a widthwise direction of the web at an end portion facing the web. The irradiation port (61) is formed between first and second parallel portions (62b, 63b) where a first plate member (62) and a second plate member (63) parallelly face each other. The web under conveyance is irradiated with linear light. It is possible to provide a lighting device capable of irradiating only an inspection region of a sheet or a web with light.

A reading apparatus that reads an image formed on a document while transporting the document, the reading apparatus includes a first reading section that reads, as a read image, one of specularly reflected light or diffusely reflected light which is reflected from the document on a reading glass through which the moving document passes, and a second reading section that reads, as a read image, the other of the specularly reflected light or the diffusely reflected light which is reflected from the document on one side of a transport path through which the document is transported.

An image processing apparatus comprises a scanner section and an area determination section. The scanner section reads the light reflected from an original document after the light penetrates a light diffusion sheet to output first image data, wherein the light diffusion sheet has a surface for diffusing the light reflected from the original document including a mirror reflection area; and the area determination section determines the mirror reflection area with respect to the first image data output from the scanner section.

A lighting device (23) irradiates a web under conveyance with light. The lighting device includes a light source (43), and an irradiation port (61) configured to open linearly in a widthwise direction of the web at an end portion facing the web. The irradiation port (61) is formed between first and second parallel portions (62b, 63b) where a first plate member (62) and a second plate member (63) parallelly face each other. The web under conveyance is irradiated with linear light. It is possible to provide a lighting device capable of irradiating only an inspection region of a sheet or a web with light.

An image reading device includes plural light sources that irradiate an image reading target with light at different angles; and a switching mechanism that sequentially switches the light incident to the image reading target from the plural light sources during an image reading operation on the image reading target.

A document reader system configured to capture an image of a document is described. The document reader system includes a document reader having a transparent scan area, a light source, an optical filter, and an image sensor. The transparent scan area is configured to receive the document on a first side of the transparent scan area. The light source is positioned on a second side of the transparent scan area opposite the first side and is configured to emit light towards the transparent scan area. The optical filter is positioned between the light source and the transparent scan area and has a variable light transmission configured to modify light intensity of the light emitted by the light source. The image sensor positioned on the second side of the transparent scan area and configured to capture the image of the document on the first side of the transparent scan area.