A position detecting device includes circuitry. The circuitry is configured to control a reading device to detect, as a first detection result, an outer shape of a processing subject and a position of an image pattern on the processing subject; control the reading device to detect, as a second detection result, a mark arranged on a position reference member, the mark corresponding to a predetermined position in the reading device; and detect a first correction value of the reading device and a second correction value of the reading device corrected by the first correction value on basis of the second detection result and reflect the first correction value and the second correction value to the first detection result to correct a processing position in the processing subject.

A method includes operating a computer of an image forming apparatus, using, as a target image, an adjustment image including a center image representing a center thereof in a width direction, to: perform test processing of generating a print image by superimposing an outline image on an adjustment image after further shifting the outline image in the width direction by a first distance, and then executing printing processing; and adjust a relative position such that each of a difference between the first distance and a length in the width direction of a margin region lying along one lateral edge of a sheet, and a spaced-apart distance between the center of the sheet in the width direction and the center of the adjustment image in the width direction, represented by the center image formed on the sheet, becomes 0.

An image processing device includes: a fold unit that folds an adjustment sheet, in which an adjustment pattern including at least one line segment is formed, over the at least one line segment based on a predetermined reference fold position; an image reader that reads an image of the adjustment pattern of the adjustment sheet with the adjustment sheet folded by the fold unit unfolded; a position identifying unit that identifies, as a position of a fold line, a position of distortion of the at least one line segment or a predetermined position of an area which appears in the image of the adjustment pattern read by the image reader; and a fold position adjusting unit that adjusts a fold position of the fold unit based on a difference between the position of the fold line identified by the position identifying unit and the reference fold position.

An image reading device includes a marking part that applies a predetermined mark to a margin of a rear end of a document having passed through an image reading position, a mark erasing part that erases the predetermined mark when the document is discharged from a sheet discharge port, and an image data processing unit that determines whether the predetermined mark exists in image data of a document image read by an image reading unit and erases the image data of the document image when it is determined that the predetermined mark exists.

To provide a sheet size determining apparatus capable of appropriately determining a sheet size. Specifically, a sheet size detection result is acquired by a sensor, and when there are a plurality of candidate sheet sizes corresponding to the acquired detection result, a sheet size is determined from the plurality of candidate sheet sizes in response to a setting of the operation device that indicates sheet sizes.

A printing apparatus capable of adding number information differing from copy set to copy set, to a printing target image includes a judging unit configured to judge whether to add user information indicating a current user to a printing target image, and a determination unit configured to determine a position to which the number information is to be added, based on a result of the judgment performed by the judging unit.

A reading device includes a position reference member and a reader. The position reference member has a reference pattern that includes a line extending in a prescribed direction. The position reference member is configured to relatively move in a direction orthogonal to the prescribed direction. The reader includes a plurality of sensor chips, each of the sensor chips including a plurality of pixels. The reference pattern corresponds to each of the sensor chips of the reader.

A reading device including a position reference member having a reference pattern having a line extending along a first direction of the position reference member, the position reference member movable in a second direction orthogonal to the first direction; a reader including a plurality of sensor chips arranged along the first direction, each of the sensor chips having a length defined by a plurality of pixels; and circuitry. The circuitry is configured to detect the reference pattern of the position reference member using the reader; determine coordinates of at least two sensor chips in the second direction, based on the detected reference pattern of the position reference member; and correct a position of a reading target in the second direction based on the coordinates determined for the at least two sensor chips of the reader in the second direction.

An image forming apparatus includes an identification-mark making unit. The identification-mark making unit makes a page identification mark for identifying a page, on a predetermined position of a paper sheet during printing. The identification-mark making unit, based on the page identification mark made in a previous printing, includes a correction/addition mark that indicates an existence of a correction page or an additional page since the previous printing in a part of the page identification mark when a new print output is performed.

An image reading apparatus includes the following. A conveyor conveys a sheet on which an image is formed by an image forming apparatus. An image reader reads the image formed on the sheet. A storage stores a speed variation profile which shows a speed variation for conveying the sheet with the conveyor when the image is read by the image reader. A controller, based on a speed variation profile stored in the storage, controls the conveyor to cancel a variation in speed shown by the speed variation profile, controls the image reader to read a reference mark formed on a sheet by the image forming apparatus, and obtains a forming position of the reference mark.