In accordance with an embodiment, an image reading apparatus comprises a sensor configured to read an image in a main scanning direction; a first reference plate; a second reference plate; and a processor configured to determine a parameter for shifting shading correction data on the basis of first reference data obtained through reading on the first reference plate by the sensor and second reference data obtained through reading on the second reference plate by the sensor, set the shading correction data on the basis of data obtained through the reading on the first reference plate by the sensor, acquire image data at each reading position in the sub-scanning direction by the sensor and carry out shading correction on the image data on the basis of the shading correction data shifted according to a shift amount at the each reading position obtained from the parameter.

An image forming apparatus includes an image reading unit, an image forming unit, a discharge unit, and a discharge tray. The image reading unit is configured to read a document placed on a document placement table by moving and scanning of a scanning body in a sub-scanning direction. The image forming unit is configured to form an image read by the image reading unit on a paper sheet. The discharge unit is configured to discharge the paper sheet on which an image is formed by the image forming unit to a direction perpendicular to the sub-scanning direction. The discharge tray is on which the paper sheet from the discharge unit is to be placed with a space portion at a lower side of the image reading unit. A bottom surface of a housing of the image reading unit facing the discharge tray is constituted of a first surface and a second surface. The first surface is a surface at a front side of the discharge unit in a discharging direction and high with respect to the discharge tray. The second surface is a surface at a back side of the discharge unit in the discharging direction lower than the first surface with respect to the discharge tray. A pulling member and/or a movable wiring are/is arranged at an upper side of the second surface inside the housing. The pulling member is configured to move the scanning body back and forth in the sub-scanning direction. One end portion of the movable wiring is secured to the scanning body.

An image scanner includes an image sensor with a plurality of scanning elements arrayed in a main scanning direction, a carriage carrying thereon the image sensor, a pair of pulleys, a belt looped around the pulleys, a connector, and a restricting member. The connector protrudes from the carriage and is connected to the belt which is inserted in an entry port of the connector. When the belt is driven to rotate, the connector moves with the belt and moves the carriage in a sub-scanning direction. The restricting member contacts the belt when, in a state where the carriage is at a standby position, the belt shifts in a disengaging direction in which the belt tends to disengage from the connector through the entry port.

In accordance with an embodiment, an image reading apparatus comprises a sensor configured to read an image in a main scanning direction; a first reference plate; a second reference plate; and a processor configured to determine a parameter for shifting shading correction data on the basis of first reference data obtained through reading on the first reference plate by the sensor and second reference data obtained through reading on the second reference plate by the sensor, set the shading correction data on the basis of data obtained through the reading on the first reference plate by the sensor, acquire image data at each reading position in the sub-scanning direction by the sensor and carry out shading correction on the image data on the basis of the shading correction data shifted according to a shift amount at the each reading position obtained from the parameter.

A driving device is used in an image reading apparatus, and reciprocates a scanning unit for reading an image on an original. The driving device comprises a pull member, a driving pulley which transmits driving force to the pull member, a following pulley which applies tension to the pull member and a pulley holder having a pulley axis which holds the following pulley rotatably. Then, the pulley axis has a lock pawl capable of locking an upper end portion of the following pulley and canceling engagement with the following pulley by being tilted toward a side of an axial center by elastic deformation. Furthermore, the lock pawl is arranged at a side of a tension acting direction from the pull member to the following pulley except the farthest position from the driving pulley among positions in a circumferential direction of the pulley axis. It is possible to attach and detach the following pulley easily at a time of maintenance or the like.

An image reading device has a motor, an optical sensor (a light emitting portion, a light receiving portion), a carriage, a motor, a moving portion for rotating a belt, a pulse generating gear provided with a plurality of light shielding teeth along its circumference, and a control portion. The light shielding teeth of the pulse generating gear pass through a gap between the light emitting portion and the light receiving portion. First and second widths are set such that the movement amount of the pulse generating gear resulting from the motor rotating one step is equal to or larger than both the width of each of the light shielding teeth (first width) and the width of the interval between adjacent light shielding teeth (second width). The control portion recognizes when, during standby of the carriage, the level of an output signal changes.

An image reading apparatus includes a sensor unit configured to move, a first driven pulley and a second driven pulley disposed apart from each other in a movement direction of the sensor unit, a drive pulley and a third driven pulley disposed between the first driven pulley and the second driven pulley in the movement direction, and a belt wound around the first driven pulley, the second driven pulley, the drive pulley, and the third driven pulley. The belt is bent at positions where each of the first driven pulley, the second driven pulley, and the drive pulley contacts an inner surface of the belt and is bent at a position where the third driven pulley contacts an outer surface of the belt.

An image reading apparatus includes a conveyance unit, a casing, a reading unit, a support shaft, a first cable, and a second cable. The reading unit includes a reading sensor configured to read an image of the sheet conveyed in the conveyance path through the transparent member. The support shaft supports the reading unit in a manner of moving in a moving direction orthogonal to a longitudinal direction of the reading unit. The first cable is connected to a first connecting portion disposed in the reading unit, the first cable being held by the reading unit on one side in the longitudinal direction with respect to the support shaft. The second cable is connected to a second connecting portion disposed in the reading unit, the second cable being held by the reading unit on the other side in the longitudinal direction with respect to the support shaft.

An image reading apparatus includes a document supporter, a guide, a carriage, and a reader. The carriage has a recessed portion. A first protrusion, a second protrusion, a third protrusion, a fourth protrusion, a fifth protrusion, and a sixth protrusion are provided on the recessed portion. Each of the first protrusion, the second protrusion, the third protrusion, and the fourth protrusion has a distal end portion in a protruding direction thereof, and the distal end portion is in contact with the guide when the carriage is mounted on the guide. A protruding amount of each of the fifth protrusion and the sixth protrusion in a protruding direction thereof is less than that of each of the first protrusion, the second protrusion, the third protrusion, and the fourth protrusion.

An image reading apparatus includes an image scanning unit that is provided with a holding portion holding a flexible flat cable. The holding portion is protruded toward an upstream side in a sub scanning direction, and provided with a second wall part. The flexible flat cable that is extended from a connector is brought into contact with the second wall part. As for the flexible flat cable, a downward movement is regulated by a lower holding portion and an upward movement is regulated by an upper holding portion. Accordingly, the flexible flat cable does not rise.