An image forming apparatus includes a rotating body to form an image, a sensor to detect a home position of the rotating body, a processor to acquire image density data of the image formed by the rotating body in odd-numbered rotation and even-numbered rotation of the rotating body separately based on a rotation home position signal output by the sensor, extract an image density fluctuation caused by a rotation of the rotating body, and correct an image forming condition based on the image density fluctuation.

A printer (300) is disclosed. The printer has two scanners (336, 338) in the paper path of the printer located after the print zone (346). The two scanners are spaced apart from each other by a known distance A and overlap each other in a direction perpendicular to the media axis of travel. The two scanners capture a first and second image of the media.

A medium conveying apparatus includes a conveyance roller to convey a medium, a DC motor to drive the conveyance roller, a processor to rotate the DC motor, an encoder to output a first pulse signal whose cycle varies according to a rotation speed of the DC motor, and an imaging device to acquire an image acquired by imaging a conveyed medium in response to a pulse of a second pulse signal whose cycle is constant. The processor detects a number of pulses of the second pulse signal included in a predetermined cycle of the first pulse signal, and discards images acquired by the imaging device in the same number of pulses as difference between the detected number of pulses and a reference number, in a next cycle of the predetermined cycle of the first pulse signal, when the detected number of pulses exceeds the reference number.

An image processing apparatus comprising: a storage unit configured to store image data read by scanning, with a linear sensor including pixels arranged in a main-scanning direction, an original in a sub-scanning direction orthogonal to the main-scanning direction, an acquisition unit configured to acquire inclination information indicating inclination of the image data, and a readout unit configured to read out the image data from the storage unit, with shifting, in accordance with the inclination information, a line position in the sub-scanning direction by each predetermined number of pixels in the main-scanning direction, wherein the readout unit reads out the image data from the storage unit, based on the inclination information, differentiating the predetermined number of pixels between an edge in the main-scanning direction and other parts.

An image processing device includes a reception unit that receives an input image signal, and a synchronization signal used to generate an output image signal on a basis of the input image signal. In a case in which, after receiving the synchronization signal, the reception unit does not receive a next synchronization signal within a predetermined reception period, the reception unit conducts an automatic reception process that treats the next synchronization signal as being received.

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.

An image reader including a document table having a reference point, a first region of a sheet having a predetermined size when a vertex of the sheet is positioned on the reference point, and a second region, a changing mechanism changing a reading position in a sub scanning direction, and a controller configured to control the changing mechanism to change the reading position to a first position such that a distance in the sub scanning direction between the reference point and the first position corresponds to a length of the predetermined sheet size in the sub scanning direction, acquire specific digital data of the second region through image reading in the first position with a light source turned off, compare a particular value of the specific digital data with a criterion value within the second region, and determine a state of a document cover based on the comparison.

An image reading apparatus, having a conveyer, a sheet tray, an obtaining device, a memory, a determining device, and a controller, is provided. The controller determines whether information concerning pixels in the memory indicates edge positions or edge absence in in read-image data concerning a sheet, detects an upstream leading-end position and a downstream leading-end position, detects upstream continuing pixels and downstream continuing pixels, detects an upstream lateral-end position and a downstream lateral-end position, calculates a line representing an upper end of the sheet based on the upstream leading-end position and the downstream leading-end position, calculates an upstream corner position and a downstream corner position based on the upstream and downstream lateral-end positions and the line representing the upper end of the sheet, and calculates a width of the sheet based on the upstream corner position and the downstream corner position.

An image scanning apparatus includes a controller configured to execute a first operation of checking whether a standby position is coincident with a home position in response to determining that an open signal is not output from a cover sensor while an image scanner is changing a scanning position from a scanning end position toward a scanning start position after completion of image scanning, and to execute a second operation in response to determining that the open signal is output from the cover sensor while the image scanner is changing the scanning position, the second operation including moving the scanning position to a particular position between the standby position and the scanning end position, without executing the first operation.

An image processing apparatus includes an image acquisition section that acquires pieces of image data acquired by performing image reading in a sub scan direction in a unit of a line extending in a main scan direction, an orientation changing section that changes an orientation of each of data images represented by the respective pieces of image data acquired by the image acquisition section, and an image processing section that performs image processing serially on the pieces of image data acquired by the image acquisition section. The image processing section performs the image processing every predetermined number of pieces of image data serving as a predetermined processing unit. The image processing section changes the predetermined processing unit for the image processing to a processing unit different from the predetermined processing unit in a case where the orientation is changed by the orientation changing section.