An image reading system includes a reading section that is provided in a conveyance path for conveying a document and that reads an image from the document conveyed through the conveyance path; a rotating member that is disposed opposite to the reading section across the conveyance path and rotates with a main scanning direction of the reading section as an axial direction; a flat white reference surface that is provided on an outer periphery of the rotating member and from which white reference data is read by the reading section; reference markers that are provided on both end sides of the white reference surface in the axial direction and are read by the reading section; and a processor that, in a case where rotation positions of the rotating member when the respective reference markers are read are different, sets a reading reference position of the white reference data between the read rotation positions of the rotating member and controls the reading section to perform reading at a position based on the reading reference position.

A scanner includes a platen having a surface supporting items for scanning, and a projector adjacent (e.g., above or below) the platen. The projector projects light displaying patterned alignment marks on the items located on the platen. The patterned alignment marks identify an alignment position for the items to be located on the platen for properly aligned scanning. The projector projects different patterned alignment marks based on different characteristics of different items to be scanned.

A method for determining a media size of a target scanned on the platen of the flatbed scanner using a fiducial placed on a backer of the flatbed scanner at a predetermined location. The fiducial is comprised of a plurality of objects, either placed in a predetermined pattern or randomly within a fiducial frame. A target is placed on the platen of the flatbed scanner and scanned along with the backer. The scanned image data of the target and backer is searched for the fiducial image. When the fiducial image is found, the media is selected to be of a first target type having a first length, and, when the fiducial is not found the target is selected to be of a second target type have a second length longer than the first length.

An image reading apparatus includes a gray reference member, a reading unit, an adjusting unit, a calibration unit, a storage unit, and a control unit. The control unit is configured to execute a first preprocessing and a second preprocessing. The first preprocessing includes: acquiring first black data from one line worth of image data; acquiring white data; calculating white-black difference data; acquiring first light gray data; and calculating first light gray-black difference data. The second processing includes: acquiring second black data from the one line worth of the image data; acquiring second light gray data; calculating second light gray-black difference data; calculating a change ratio by dividing the second light gray-black difference data by the first light gray-black difference data; and calculating calibration data by multiplying the white-black difference data by the change ratio. Shading of the image data is calibrated in response to the calibration data.

An image forming apparatus acquires shape data indicating a shape of a sensing sheet conveyed along a conveyance route, adjusts a position of a first image in first image data including the first image on the basis of a positional relationship between a sheet region in the acquired shape data and a first reference position in the shape data, forms an image based on the adjusted first image data on the sensing sheet, and senses an amount of positional misalignment of an imaging portion to be used to acquire the shape data by using the sensing sheet on which the image has been formed.

According to examples, an apparatus may include a processor and a memory on which are stored computer-readable instructions that, when executed by the processor, may cause the processor to identify first property values along an image of a pattern. The first property values may be identified based on a first signal corresponding to an image of the pattern captured by an imaging sensor. The pattern may be positioned at a spaced relation with respect to the imaging sensor. The processor may receive a second signal corresponding to a second image captured by the imaging sensor, and may identify, from the second signal, second property values along the second image. Based on a determination that the second property values differ from the first property values, the processor may determine that a beginning of a media is positioned to be imaged by the imaging sensor.

A printing system includes a substrate support, a printhead assembly positioned facing the substrate support, and an imager. The printhead assembly includes a plurality of dispensing nozzles extending in an ejection direction towards the substrate support and a plurality of marks. The imager is movable relative to the printhead assembly and oriented in a direction opposite to the ejection direction for capturing at least one image including the plurality of marks indicating positions of the plurality of dispensing nozzles in the printhead assembly.