An image reading apparatus including: an angle detector configured to detect a first state in which a pressure plate is at a first angle with respect to a transparent member and a second state in which the pressure plate is at a second angle smaller than the first angle; a size determiner configured to determine a size of the original in a main scanning direction based on a reading result of a reader; and a controller configured to switch a first size determination mode in which a light source is turned on when a waiting state in which an angle of the pressure plate is larger than the first angle is changed to the first state, and a second size determination mode in which the light source is tuned on when the first state is changed to the second state.

An image reading device includes a document tray, a linear conveyance path, a curved conveyance path, a document conveyance device, a scanning device, a length detecting device, an operation device, and a controller. A plurality of conveyance rollers are disposed at a predetermined first interval in the linear conveyance path. In the curved conveyance path, a plurality of conveyance rollers are disposed at a predetermined second interval longer than the first interval. When accepting through the operation device an instruction for conveying an original document through the curved conveyance path, the controller allows conveyance of the original document through the curved conveyance path when a length of the original document detected by the length detecting device is not shorter than the second interval or disallows conveyance of the original document through the curved conveyance path when the detected length of the original document is shorter than the second interval.

The image processing apparatus adds a first image that includes a predetermined image feature, to a read image of the document based on a detection result in the detecting, and transmits a second image of the predetermined image size specified in the read instruction, to the information processing apparatus. The information processing apparatus obtains the read image of the document included in the second image transmitted in the transmitting. The image processing apparatus adds the first image such that in the second image the first image is provided on the outside of the read image of the document, based on at least one of a width and a height of the document detected in the detection. The information processing apparatus obtains the read image of the document based on the predetermined image feature.

An image reading apparatus includes: a reading unit, which is configured to read an original placed on an original table in a main scanning direction by irradiating the original with light; and a sub-scanning size detector, which is configured to detect presence or absence of the original on the original table by radiating invisible rays. When the platen cover forms an angle of equal to or smaller than a first angle with respect to the original table, the image reading apparatus determines a size of the original in a sub-scanning direction in accordance with a detection result acquired from the sub-scanning size detector. When the platen cover forms an angle equal to or smaller than a second angle, which is smaller than the first angle, with respect to the original table, the image reading apparatus determines a size of the original in the main scanning direction.

A medium transport apparatus includes: a feed unit feeds a medium to a transport direction; a first detection unit disposed upstream of the feed unit, and detects movement of the fed medium; a second detection unit disposed downstream of the first detection unit and detects an inclination of the medium; and a control unit detects the inclination of the medium based on a signal of the second detection unit and stop transfer of the medium when the inclination exceeds a threshold value, and the plurality of the threshold values have a relationship such that when a medium length in the transport direction is a second length being shorter than a first length, a relatively higher value is produced than in a case in which the medium length is the first length, and the control unit selects a threshold value based on a detection value of the first detection unit.

A multi-feed detection apparatus includes a conveyance roller, an ultrasonic sensor for generating an ultrasonic signal, an imaging device to image the medium being conveyed by the conveyance roller and sequentially generate a line image, and a processor to detect a width of the medium in each line image for each line image, detect a vertex count of a medium included in the sequentially generated line image based on the width of the media in the each line image, detect a length of the medium in a direction perpendicular to the medium width, estimate a shape of a medium based on the vertex count and the length of the medium, and detecting media multi-feed by comparing the ultrasonic signal with a predetermined threshold value, and change the predetermined threshold value or stop detection of the medium multi-feed, based on the estimated shape of the medium.

An image reading apparatus comprises a platen, a support, a reader, an open/close unit, a first obtainer, a mark, a positioning member, and a determiner. A position of the mark on a pressing surface of the cover, is provided at a position at which, in a case where a sheet of a maximum size among standard sizes that can entirely fit in a readable range of the reader is positioned with respect to the positioning member, at least a portion of the mark is not hidden by the sheet as viewed from the reader.

An information processing apparatus includes a memory storing instructions and a processor to execute the instructions to perform operations. Four sides of a document included in captured image data are detected. Lengths of the detected four sides of the document are calculated. The operations further include determining which of a plurality of predefined paper sizes corresponds to the document based on the calculated lengths of the four sides. The determined corresponding paper size is set as a document size of the document.

An image reading apparatus includes a detection unit provided at a position separated from a positioning portion by a predetermined distance in a first direction, a discriminator configured to determine a length, in the first direction, of a document, and a setting unit that sets a start position to a first position if a detection position at which the detection unit detects the document is not included in a range, in a second direction, of the transparent member that is covered by the document, and sets the start position to a second position if the detection position is included in the range and the detection unit does not detect the document, wherein, in the first direction, the distance between the first position and the positioning portion is larger than the distance between the second position and the positioning portion.

The image processing apparatus adds a first image that includes a predetermined image feature, to a read image of the document based on a detection result in the detecting, and transmits a second image of the predetermined image size specified in the read instruction, to the information processing apparatus. The information processing apparatus obtains the read image of the document included in the second image transmitted in the transmitting. The image processing apparatus adds the first image such that in the second image the first image is provided on the outside of the read image of the document, based on at least one of a width and a height of the document detected in the detection. The information processing apparatus obtains the read image of the document based on the predetermined image feature.