A method for testing the reliability of an error detection of an image inspection method by using a computer includes producing a defective test image by superposing specific error elements on an error-free reference image, carrying out the image inspection method with the defective test image, comparing the errors found by the image inspection method with the error set to be expected with the aid of the known errors added to the test image, and evaluating the reliability of the image inspection method with the aid of the difference between found and expected errors.

A lighting device (23) irradiates a web under conveyance with light. The lighting device includes a light source (43), and an irradiation port (61) configured to open linearly in a widthwise direction of the web at an end portion facing the web. The irradiation port (61) is formed between first and second parallel portions (62b, 63b) where a first plate member (62) and a second plate member (63) parallelly face each other. The web under conveyance is irradiated with linear light. It is possible to provide a lighting device capable of irradiating only an inspection region of a sheet or a web with light.

A first surface of a first sheet has a second image formed in advance. An image forming system generates reference data based on a result of reading an image on the first surface of the first sheet on which a first image is not formed, generates first image data that represents a result of reading an image on the first surface of the first sheet having the first image formed on the first surface, and determines, based on the reference data and the first image data, a relative position between the first image and the second image on the first surface of the first sheet.

An apparatus can be used for inspecting printed images for a printing or finishing machine with continuously moved printed products. An illumination unit with a light source illuminates a recording region and an image capture apparatus with at least one camera, for example a line scanning camera, is set up to capture an image inside the recording region, which extends over the width of the printed product, wherein the image capture apparatus is set up to generate a multi-line partial image.

A method for controlling a printing process is disclosed. The method includes printing a printing material by a printing unit on a basis of data of a prepress stage. A printed result on the printing material is compared with a desired value and a correction value is derived from the comparison. The data of the prepress stage is corrected with the correction value.

An image inspection apparatus for checking an image printed on a recording medium includes: a reference pixel obtaining unit configured to generate a reference image and obtain a first pixel value from the reference image; a print pixel obtaining unit configured to extract an image printed area and obtain a second pixel value from the image; an offset processing unit configured to add a non-image-printed area; and an image checking unit configured to compute a difference between the first image pixel value and the second image pixel value and detect an error when the difference is higher than a predetermined threshold value, wherein the non-image-printed area contains a third pixel value that is different from the first pixel value or the second pixel value, and the image checking unit suspends a determination whether or not there is an error in the image printed area associated with the non-image-printed area.

A flexographic printing press for printing a substrate web comprises at least one printing unit and at least one central cylinder. A plurality of printing couples are arranged around the periphery of the at least one central cylinder. A horizontally aligned dryer unit, having at least one guide element, is arranged above the printing unit in a vertical direction. The at least one horizontally aligned dryer unit has at least two dryer sections with one dryer section being arranged separated from the next dryer section by at least one diverting assembly. The at least one flexographic printing press has at least one roll unwinder and at least one roll winder. The at least one roll unwinder and the at least one roll winder are arranged on opposite sides of the at least one central cylinder.

According to aspects of the embodiments, there is provided a method of determining the amount of fountain solution employed in a digital offset lithography printing system. Fountain solution thickness is determined from diagnostic images that are printed and analyzed using the existing Image Based Controls (IBC). An analysis of the density of solids, halftones, and background as a function of the fountain solution control parameter is performed to decide on the appropriate level of fountain solution. A latitude window of control parameters is then derived for which the digital offset lithography printing system in operation minimizes the undesirable effects of too much or too little fountain solution.

A sheet-fed printing machine comprises two sheet-fed printing units; of which a first is configured as a sheet-fed simultaneous printing unit and has two collector cylinders, which interact with one another and each have an axis of rotation. An axial plane contains the axes of rotation of the collector cylinders. A reference plane contains an axis of rotation of this type and has a horizontal surface normal. An intersection angle between the axial plane and the reference plane is, at a maximum, 45 degrees. A first one of the sheet-fed simultaneous printing units has exactly four plate cylinders, of which exactly two are arranged such that they directly interact with the first collector cylinder and has exactly two others which are arranged such that they directly interact with the second collector cylinder. A second sheet-fed printing unit has at least one impression cylinder and at least one plate cylinder, which is arranged such that it directly interacts with the impression cylinder and which is configured a screen printing plate cylinder, or as a flexo plate cylinder or as a numbering plate cylinder. The two collector cylinders of the first printing unit and the impression cylinder of the second printing unit have the same circumference.

Techniques for manufacturing a light field print using a printing press. The techniques include: identifying at least one characteristic of the printing press at least in part by printing at least one calibration pattern; obtaining content to be rendered using the light field print, the content comprising multiple scene views; generating, based at least in part on the content and the at least one characteristic of the printing press, a front target pattern and a back target pattern; and using the printing press to: print the front target pattern on a first side of a substrate; and print the back target pattern on a second side of the substrate.