A reading module has a light source, an optical system having a mirror array and an aperture stop portion, a sensor in which a plurality of image regions where the image light is converted into an electrical signal are arranged; a housing; and a light-shielding wall shielding stray light striking the image regions. In the mirror array, a plurality of reflective mirrors whose reflection surfaces are aspherical concave surfaces are coupled together in an array in the main scanning direction. The optical system is fixed to on the case housing at one point in the main scanning direction, and the light shielding walls are arranged at a positions displaced deviated by a predetermined amount from boundaries between the image regions in the direction opposite to the fixed side of the optical system.

According to aspects of the embodiments, there is provided process and architecture for enabling multiple digital micromirror devices (DMDs) that include optical modulation elements configured to modulate light outputting from a light source, and a projection unit configured to project light modulated by the optical modulation elements on a printing plate. Image defects due to misalignment in the cross-process direction of the output from the DMDs are discovered by using a single test pattern image and combined with knowledge of how individual pixels are rendered to register printing elements which can render a variable number of pixels. Misalignment errors can be corrected by selecting a different set of mirrors for a given DMD.

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.

Provided is an image forming apparatus capable of accurately returning a carriage to a home position without having to turn ON a light source in the process of returning the carriage to the home position. A first reading-position-detection plate is arranged inside of a reading width of a line sensor and outside of a document-image-reading width. A second color region has a length that gradually increases in the main scanning direction as going away from the home position of the carriage. A reading-position-detecting unit detects the length in the main scanning direction of the second color region on the basis of output from the line sensor. A movement-distance-converting unit converts this length to a movement distance to the home position. A movement-control unit causes the carriage to move toward the home position just the movement distance.

An information reading device that optically reads information recorded on an information recording medium may include a transparent placement member; a first illumination light a second illumination light a first optical system to read information on the lower surface of the information recording medium; a second optical system to read information on the upper surface of the information recording medium; and a cover member. The second optical system may include a reflection mirror. A medium disposition part may be formed by the placement member and the cover member. The upper surface portion and the side surface portions may be transparent. The second illumination light may be disposed on outer sides of the medium disposition part in the left-right direction. Light emitted from the second illumination light and transmitted through the side surface portions may be irradiated onto the upper surface of the information recording medium placed on the placement member.

A reading module has a light source, an optical system imaging, as image light, reflected light of light radiated from the light source to a document, a sensor where a plurality of imaging regions for converting the image light imaged by the optical system into an electrical signal are arranged next to each other in the main scanning direction, and a housing the light source, the optical system, and the sensor. The optical system has a mirror array where a plurality of reflection mirrors whose reflection surfaces are aspherical concave surfaces are coupled together in an array in the main scanning direction, and an aperture stop portion adjusting the amount of the image light reflected from the reflection mirror. The amount of the image light striking the reflection mirror is increasingly small from opposite end parts of the reflection mirror toward its central part in the main scanning direction.

A reading module has a light source, an optical system having a mirror array and an aperture stop portion, a sensor in which a plurality of image regions where the image light is converted into an electrical signal are arranged; a housing; and a light-shielding wall shielding stray light striking the image regions. In the mirror array, a plurality of reflective mirrors whose reflection surfaces are aspherical concave surfaces are coupled together in an array in the main scanning direction. The optical system is fixed to on the case housing at one point in the main scanning direction, and the light shielding walls are arranged at a positions displaced deviated by a predetermined amount from boundaries between the image regions in the direction opposite to the fixed side of the optical system.

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 information reading device that optically reads information recorded on an information recording medium may include a transparent placement member; a first illumination light a second illumination light a first optical system to read information on the lower surface of the information recording medium; a second optical system to read information on the upper surface of the information recording medium; and a cover member. The second optical system may include a reflection mirror. A medium disposition part may be formed by the placement member and the cover member. The upper surface portion and the side surface portions may be transparent. The second illumination light may be disposed on outer sides of the medium disposition part in the left-right direction. Light emitted from the second illumination light and transmitted through the side surface portions may be irradiated onto the upper surface of the information recording medium placed on the placement member.

An image reading device includes a housing, a carriage, and a lock mechanism. The housing includes an exterior member and a document sheet placement surface. The carriage is configured to move in the housing along a predetermined specific direction. The lock mechanism is configured to lock the carriage to a lock position. The lock mechanism includes a supported portion and a locking portion. The supported portion is supported by the housing and provided between the exterior member and the carriage disposed at the lock position. The locking portion moves between a first position and a second position in response to a magnetic force of a magnet disposed at a specific position on the exterior member so as to, at the first position, engage the supported portion with the carriage disposed at the lock position, and at the second position, release engagement between the supported portion and the carriage.