A print apparatus is disclosed. In some examples, the print apparatus comprises a print head to deposit print agent onto a substrate; a detector to detect a fiducial; a first light source to back-illuminate the substrate, such that light from the first light source is to be detected by the detector through the substrate; and processing apparatus. The processing apparatus is to operate the print head to deposit print agent to form a first fiducial on a first side of the substrate, the first fiducial comprising a shape of a first colour and having a first dimension, and a background of print agent of a second, different colour, wherein the first dimension of the shape does not exceed a corresponding dimension of the background; operate the print head to deposit print agent to form a second fiducial on a second, opposite side of the substrate, the second fiducial comprising an inverted version of the shape of the first colour; operate the first light source to back-illuminate the substrate; operate the detector to detect the first and second fiducials; and determine whether the first fiducial is aligned with the second fiducial. A method and a machine-readable medium are also disclosed.

In a system that verifies a print detect in a printed sheet, inconsistency between the sheet side at the time of reference image registration and that at the time of verification processing is prevented from occurring without imposing complicated work on a user. An image on a sample sheet is registered in advance as a reference image in association with the sheet side and at the same time, the sheet discharge setting for the sample sheet is stored. Verification is performed by matching the sheet side associated with the reference image and the verification-target side of the printed sheet based on the sheet discharge setting stored as a sheet discharge setting in the print processing.

Techniques for characterizing an optical system (for example, a printer verifier) are provided. In this regard, the optical system may be characterized for scanning a printed image. The characterization of the optical system includes determining an effective aperture size of the optical system, and correspondingly an effective resolution at which the optical system can be configured to scan a portion of the printed image according to verification requirements.

An inspection apparatus that inspects the quality of a printed product printed by a print apparatus receives information indicating a reference image, from an information processing apparatus that transmits a print job to the print apparatus. The inspection apparatus acquires the reference image based on the information indicating the reference image. The inspection apparatus receives from the print apparatus a scanned image of the printed product printed based on the print job received from the information processing apparatus, and inspects the quality of the printed product based on a comparison between the received scanned image and the acquired reference image.

An example image forming apparatus includes an image forming apparatus, a processor, and a memory storing instructions executable by the processor. The processor of the image forming apparatus executes the instructions to render a print job, obtain information regarding a pattern for determining print quality from a rendered image of the print job, scan, through the image forming job unit, a document on which the rendered image is printed, and determine the print quality based on a scanned image of the document and the obtained information regarding the pattern.

An information processing apparatus capable of executing adjustment of an image formation position at a timing determined based on the number of printed sheets according to a user's request. Adjustment modes for use in adjusting geometrical characteristics of an image which is printed on a sheet are displayed for causing an image forming apparatus to print an adjustment chart. A controller receives first information indicating whether or not to execute a first adjustment mode for causing the image forming apparatus to print the adjustment chart based on the number of sheets on which images have been printed by the image forming apparatus, and receives second information indicating whether or not to execute a second adjustment mode for causing the image forming apparatus to print the adjustment chart based on a result of detection by a temperature sensor provided in the image forming apparatus.

An image forming system includes: a reading unit configured to read a test image, the test image having a determination image formed by overlapping a plurality of colors and a plurality of reference images formed with each of a plurality of reference colors; and a determination unit configured to determine a first color value of each of the plurality of reference colors based on a reading result of the reference images, determine a second color value of a plurality of pixels included in the determination image based on a reading result of the determination image, and determine whether an image defect has occurred based on an angle of a second vector corresponding to the second color value of the plurality of pixels with respect to a first vector corresponding to the first color value of each of the plurality of reference colors.

A position of a first registration mark printed on a substrate during an earlier printing operation is detected. A second registration mark is printed on the substrate during a current printing operation at a position on the substrate relative to the first registration mark based on the detected position of the first registration mark and a correction factor. An alignment difference between the position of the first registration mark and the position of the second registration mark is measured. A new correction factor for a subsequent printing operation is calculated by weighting the measured alignment difference according to a difference between the measured alignment difference and a previous measured alignment difference.

An image forming apparatus includes an image forming unit configured to form an image and a detection image on a sheet, wherein the detection image is used for detecting a geometric characteristics of an image to be formed on a sheet by the image forming unit; a fixing unit configured to fix the image and the detection image formed by the image forming unit on the sheet; a reading unit configured to read the detection image on the sheet; a reference member; and a controller configured to: adjust geometric characteristics of an image to be formed on a sheet based on a reading result of the detection image by the reading unit; and control the reading unit to read the reference member to execute shading correction based on a reading result thereof.

An image forming apparatus outputs a tone chart for calibration by a printer, reads the output tone chart by a scanner, determines whether data on a sheet is affected by a surface shape of the sheet based on the read tone chart, corrects data on a white area of the read chart based on a result of the determination, and executes calibration using the corrected data.