A quality control station (2) for a sheet element processing machine, the station having at least one camera (6) arranged for capturing images of sheet elements (4) transported through the quality control station (2), and further having a camera calibration system (10). The camera calibration system (10) having a target holder (12) for holding an optical target (14), and a drive (15) for the target holder (12). The drive (15) is adapted for displacing the target holder (12) between a rest position, in which it is outside of the viewing area (7) of the camera (6), and a calibration position in which it is arranged in the viewing area (7) of the camera (6).

A quality control station (2) for a sheet element processing machine, the station having at least one camera (6) arranged for capturing images of sheet elements (4) transported through the quality control station (2), and further having a camera calibration system (10). The camera calibration system (10) having a target holder (12) for holding an optical target (14), and a drive (15) for the target holder (12). The drive (15) is adapted for displacing the target holder (12) between a rest position, in which it is outside of the viewing area (7) of the camera (6), and a calibration position in which it is arranged in the viewing area (7) of the camera (6).

A method of inspecting images on printed products by a computer in a printing machine. Printed products are recorded and digitized by an image sensor of an image inspection system in the course of the image inspection process, and the computer compares them to a digital reference image. If deviations are found, the defective printed products are removed. The computer analyzes the deviations found in the course of the image inspection process together with further data from other system parts and from the machine, determines specific defect classes and the causes thereof based on the defects by machine learning processes, assigns the defects found in the image inspection process to the defect classes in a corresponding way, and displays the classified detected defects with their defect classes and causes to an operator of the machine so that the operator can initiate specific measures to eliminate the defect causes.

A control apparatus of a web processing system that executes predetermined processing onto a web continuously existing along a movement passage, in which the web processing system includes a rotating body that rotates while being in contact with the web, and the control apparatus controls a rotation speed of the rotating body such that a circumferential speed of the rotating body at a contact surface with the web matches a transport speed of the web.

A sheet-fed simultaneous printing machine has two directly interacting collecting cylinders with respective axes of rotation. An axial plane contains these axes of rotation. A reference plane contains such an axis of rotation of this type and has a horizontal surface normal. The intersection angle between the axial plane and the reference plane is max 0.5°. The sheet-fed simultaneous sheet printing unit has exactly four plate cylinders, of which two are arranged such that they directly interact with the first and two are arranged to such that they directly interact with the second collector cylinder. An inking unit with a respective ink supply is arranged in each plate cylinder and a supply sectional plane is determined for each ink supply, which intersects this ink supply and which also contains the axis of rotation of the corresponding plate cylinder. An intersection angle between the reference plane and a supply sectional plane of the respective ink supply is max 35°. A sheet-fed machine comprises at least one sheet-fed printing unit of this type, as well as a sheet-fed printing unit having two directly interacting impression cylinders. An intersection angle between the axial plane on one side and the reference plane on the other side is max 45°.

A sheet-fed printing machine comprises at least two sheet-fed printing units. A first sheet-fed printing unit has a first impression cylinder and a second impression cylinder, which cylinders are arranged such that they directly interact with one another and each have an axis of rotation. An axial plane contains these two axes of rotation. A reference plane contains an axis of rotation of this type and has a horizontal surface normal. These two cylinders are arranged such that an intersection angle between the axial plane and the reference plane has a maximum angle of 30°. The first sheet-fed printing unit has at least one plate cylinder, which is in direct contact with or which directly interacts with one of the impression cylinders and which is configured as a numbering plate cylinder or as a flexo cylinder or as a screen printing plate cylinder. A second sheet-fed printing unit has at least one cylinder which is configured as an impression cylinder. The impression cylinder of the first printing unit and the impression cylinder of the second printing unit each have the same circumference.

Example implementations relate to determining a correction factor that converts a measured sensor distance to a calibrated sensor distance. The measured sensor distance may be based on an amount of substrate advancement through a web printing press between detecting a mark on the substrate at a first sensor and detecting the mark at a second sensor. The calibrated sensor distance may be the separation between the first sensor and the second sensor.

Example implementations relate to determining a correction factor that converts a measured sensor distance to a calibrated sensor distance. The measured sensor distance may be based on an amount of substrate advancement through a web printing press between detecting a mark on the substrate at a first sensor and detecting the mark at a second sensor. The calibrated sensor distance may be the separation between the first sensor and the second sensor.

In a register error detection device, an image capturing unit captures an image of two first register marks of a first color printed on a substrate by a first plate cylinder of a rotary printing press and a second register mark of a second color printed on the substrate by a second plate cylinder of the rotary printing press. A calculation unit calculates a register error based on the number of pixels between a reference position located between the two first register marks and a comparison position that is based on the second register mark in the image captured by the image capturing unit.

A method of testing a functional unit includes an optical sensor system (28) for detecting an optical signal from at least a part of a moving material web (14), a data processing system (36) for valuating the optical signals, and a display (38) displaying a state of the material web (14) and arranged in a sensitive range (30) of the sensor system (28).